Amniocentesis and Chorionic Villus Sampling in Scotland

Amniocentesis and Chorionic Villus Sampling in Scotland: An audit of techniques and outcomes of all procedures over one year in Scotland

1 May 2008 – 30 April 2009

Amniocentesis and Chorionic Villus Sampling in Scotland: An audit of techniques and outcomes of all procedures over one year in Scotland 1 May 2008 – 30 April 2009 Produced on behalf of the Reproductive Health Programme, NHS Quality Improvement Scotland by: Graham Tydeman, Obstetrician, Forth Park Maternity Unit, Project Lead Charmaine Bremner, Midwife, Forth Park Maternity Unit, Project Co-ordinator Acknowledgements:

Obstetricians and local midwife co-ordinators from all over Scotland.

All cytogenetic laboratory staff.

The members of the Scottish Perinatal Obstetricians Group (Scottish Maternal Fetal Medicine Group).

Information Services Division, NHS National Services Division

Andrew Gasiorowski, Scottish Public Health Observatory, for the maps.

With particular thanks to: Edith Carrick: who spent countless hours of her own time on the design and

upkeep of the database. Without Edith this study may not have been possible. © NHS Quality Improvement Scotland 2010 First published November 2010 You can copy or reproduce the information in this document for use within NHSScotland and for educational purposes. You must not make a profit using information in this document. Commercial organisations must get our written permission before reproducing this document. www.nhshealthquality.org

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Contents

Foreword 4 Executive summary 6 Recommendations 8 1 Introduction 9 2 Methods 10 3 Auditable standards 11

3.1 Standards common to both procedures 11 3.2 Standards for amniocentesis 11 3.3 Standards for CVS 11 3.4 Justification for standards 11

4 Additional data 13 5 Results 14

5.1 Study population and background information 14 5.2 Questionnaire results 14 5.3 Audit results 15 5.4 Amniocentesis standards 17 5.5 Summary of compliance with amniocentesis standards 29 5.6 Additional information for amniocentesis 31 5.7 Chorionic villus sampling standards 33 5.8 Additional information for chorionic villus sampling 37

6 Twin pregnancies 41 7 Discussion 42 8 Conclusions 44 9 References 45 Appendices 47 Appendix 1: Steering group members 47 Appendix 2: Cytogenetic laboratories and maternity units 48 Appendix 3: Operator’s pre-study questionnaire April 2008 49 Appendix 4: Data collection form 51 Appendix 5: Pregnancy and neonatal loss form 52 Appendix 6: Microsoft Access database collection page 54 Appendix 7: Summary data from pre-audit questionnaire 55 Appendix 8: Additional data collection form for twins 56 Appendix 9: National distribution of amniocentesis and CVS procedures 57 Appendix 10: Abbreviations used 59

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Foreword

NHS Quality Improvement for Scotland (NHS QIS) should be congratulated for funding and publishing an audit report on the techniques and outcomes of amniocentesis and chorionic villus sampling (CVS). Amniocentesis is the most common invasive prenatal diagnostic procedure undertaken in the UK. Most amniocenteses are performed to obtain amniotic fluid for karyotyping from 15 completed weeks (15+0) onwards. CVS is usually performed between 11 (11+0) and 13 (13+6) weeks of gestation and involves aspiration or biopsy of placental villi. CVS may be performed using either a percutaneous trans-abdominal or a trans-cervical approach. With the introduction of first trimester screening for chromosomal anomalies, the annual rate of CVS may increase in Scotland in the future. The report focuses on operator technique and the adherence to published national guidelines. It demonstrates and documents both variation of practice between centres and also individuals within centres. One of the most important outcomes of any audit of this nature is to describe the present experience of amniocentesis/CVS in Scotland and the pregnancy outcome in women undergoing these diagnostic tests. Such an audit, in collaboration with national perinatal databases and regional cytogenetic centres ensures as complete follow-up as is possible. It is necessary to define clearly the meaning of a procedure-related pregnancy loss and also to correct for associated complications such as pre-existing congenital anomaly. The audit forming the core of this report does this and also indicates the outcomes, in terms of procedure-related pregnancy losses, for amniocentesis and CVS and the adherence to audit standards within the Royal College of Obstetricians and Gynaecologists (RCOG) Green top Guideline (2005). Scotland has particular challenges in organising perinatal care, mainly because of the diverse geographical location of the population and their access to obstetric services. The report documents the workload for the departments providing these diagnostic tests and the number of operators performing such tests. The results of the audit indicate challenges for healthcare provision for the population accessing these tests in some centres. NHS boards are recommended to review the provision of amniocentesis and CVS for their population based on the findings in this report. A change in availability of operator expertise and a rationalisation of referral centres is likely to be necessary.

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It has been an honour to chair this committee and work with the members of the committee to produce this report. The challenge for healthcare professionals and NHS QIS will be to act to suggest modifications of institutional and personal practice, and further to suggest rationalisation of centres providing prenatal diagnosis within Scotland.

Mark Kilby MD FRCOG Chair of the Steering Group Professor of Fetal Medicine School of Clinical & Experimental Medicine College of Medical & Dental Sciences Birmingham Women's Foundation Trust Edgbaston Birmingham B15 2TG

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Executive summary

Amniocentesis and CVS in Scotland

Amniocentesis and chorionic villus sampling (CVS) are the most common prenatal diagnostic procedures. They are invasive and there may be associated risks to the pregnancy. The Royal College of Obstetricians and Gynaecologists (RCOG) has published guidelines for both procedures.

With funding and support from NHS QIS and with the guidance of a steering

group, an audit of all amniocentesis and CVS procedures in Scotland for one year from 1st May 2008 to 30th April 2009 was completed.

The audit was preceded by a questionnaire sent to all units performing the

procedures in Scotland to provide baseline information. A system was devised involving local unit co-ordinators and cross checking of

sample receipt in regional cytogenetic laboratories to ensure that information was collected for every procedure carried out during the audit period.

The information gathered for each procedure was audited against standards

derived from guidelines published by the RCOG in 2005. During the study period, 1,953 amniocentesis and 241 CVS procedures were

performed on singleton pregnancies for diagnostic purposes to inform management. Multiple pregnancies were excluded from the analysis.

Rigorous follow-up was achieved to obtain information about the outcome of

pregnancies. Adequate follow-up information was not obtained in only 9 women undergoing amniocentesis and 3 undergoing CVS.

There was variation in the rates of amniocenteses performed at different sites,

from 1.5% to 5.3% of births. Although most procedures were carried out as a result of screening tests, a

significant number, 351 amniocenteses (18%) and 77 CVS (32%), were performed solely on the basis of maternal age and 25 on maternal request only, 23 amniocenteses (1.2%) and 2 CVS (0.8%).

The procedure related miscarriage rate for amniocentesis was 0.72%, within the

standard which states that it should not exceed 1% The procedure related miscarriage rate for CVS was 2.31%, slightly higher than

the standard which states that it should not exceed 2% The most significant failings related to the number of sites where the procedures

were carried out and the number of operators performing them. Too many operators performed too few procedures at too many sites.

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Amniocentesis performed on women with a maternal Body Mass Index (BMI) over 30 was associated with a higher rate of complications; the increased rate of multiple uterine entries and bloody taps was statistically significant.

The recommendations in this report relate mainly to the rationalisation of the

number of sites where procedures are performed and the number of procedures performed by individual operators. Future local audit is also suggested.

There was generally a very high level of compliance with the standards. The

findings are summarised in the table below.

Adherence to Standard % Auditable Standard

Amniocentesis CVS

Consent should be obtained before each procedure 100 100

The technique should include continuous real time ultrasound guidance

85.4 100

Aseptic technique: probe in a sterile bag and sterile gloves

85.9 91.7

Only experienced operators should perform the procedure (performing at least 10 per year) unless training under direct supervision

Operators achieving this target

Procedures performed by operators achieving this target

79.6

96.9

55.0

83.8

Amniocentesis should not be performed before 15 completed weeks

97.8 -

The outer needle diameter for amniocentesis should not be wider than 20 gauge (0.9mm)

99.5 -

>95% of amniocentesis taps should not contain blood 98.3 -

Success at the first attempt should occur in >95% of procedures

97.4 -

CVS should not be performed under 10 weeks - 100

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Recommendations

Whilst acknowledging that there was, overall, a high level of compliance with most of the standards, the following recommendations are made. 1 The service for amniocentesis and CVS in Scotland should be rationalised to

reduce the number of operators and increase the number of procedures that each performs.

2 NHS boards should examine which service option would best serve their local community. The challenge of maintaining standards in locally delivered services needs to be considered in the configuration of services for invasive prenatal diagnosis in small units. The options are likely to include patients travelling to larger units, local clinicians performing some procedures in neighbouring larger units or clinicians from larger units visiting the smaller ones.

3 The number of operators and number of procedures each performs should be re-

audited after suitable time for reflection and, where necessary, re-organisation of services. Due attention should be paid to the 2010 RCOG guidelines.

4 The number of amniocenteses as a percentage of delivery numbers in each NHS

board should be re-audited after the rationalisation recommended here. 5 Local audit of amniocentesis technique for those units where several standards were

not met should be undertaken, particularly where procedures were undertaken without continuous ultrasound guidance, there was a high bloody tap rate or a failure to achieve a sample in the first attempt.

6 Audit of the indications for amniocentesis should be considered locally, especially for

those units that undertake a higher than average number of procedures for maternal age alone. Cases where elevated alphafetoprotein (AFP) is the indication should be discussed with at least one colleague with expertise in fetal medicine, before a procedure is performed.

7 Amniocentesis procedures for women with a BMI over 30 should be carried out by

experienced operators as the rate of complications among these women is higher.

8 When combined ultrasound and biochemical screening (CUBS) is introduced more widely in Scotland, the total number of CVS procedures as well as the numbers performed by each operator and at each location should be re-audited.

9 Information on the risks associated with amniocentesis and with CVS should be

discussed with all women undergoing either procedure, particularly when no screening test has been carried out. Women should be discouraged from undergoing invasive testing without prior screening. The national rates for procedure related pregnancy loss detailed in this report should be used when counselling women.

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1 Introduction

Amniocentesis and CVS are the most common prenatal diagnostic procedures undertaken with approximately 2,000 amniocentesis and 250 CVS procedures performed each year in Scotland (figures obtained from a survey of cytogenetic laboratories in 2007). Both procedures are tests to determine whether there is a chromosomal abnormality (such as Down’s syndrome) or specific genetic abnormality (such as cystic fibrosis) affecting the pregnancy. They involve using a fine needle to obtain a sample of amniotic fluid or placental tissue respectively and both procedures can cause miscarriage. The RCOG has issued guidance on the techniques for performing amniocentesis since 1996 and for CVS since 20051,2,3. A revised version of the RCOG guideline has been published in the summer of 20104, since the completion of this audit. The UK National Screening Committee (NSC) has also produced guidance documents5,6.

Members of the Scottish Maternal Fetal Medicine Group, which includes representation from every consultant-led delivery unit in Scotland, recognised the need to audit the practice of diagnostic amniocentesis and CVS in Scotland over a full year. The audit was supported by the Scottish Committee of the RCOG and funding and support was provided by NHS QIS Reproductive Health Programme.

During the audit period, the NHS in Scotland consisted of 14 NHS board areas with 18 consultant-led delivery units. Amniocentesis was performed at 20 sites including two that had previously been consultant-led units but had recently become midwife- led units. Seven sites also performed CVS. Four units acted as tertiary referral centres and undertook prenatal diagnostic procedures for patients from other units. There were five regional cytogenetic laboratories in Scotland with four out of the five analysing samples for both amniocentesis and CVS. The project was undertaken to audit the practice of every amniocentesis and CVS procedure undertaken for purely diagnostic indications in Scotland over a one year period. Data were not collected for prenatal invasive procedures that were aimed to be therapeutic such as amnioreduction or drainage of fetal structures, even if samples were also taken for diagnostic purposes at the time.

The aims of the audit were to: compare techniques and outcomes with standards derived mainly from the RCOG

green top guideline published in 20053 publish the results for each derived standard for Scotland as a whole and

anonymously by site, and make recommendations where the derived standards were not met and to suggest

methods to close the audit cycle.

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2 Methods

A steering group was established to oversee the project, chaired by a professor of maternal fetal medicine from England. The list of steering group members is available in Appendix 1. The steering group’s remit was to establish the auditable standards; to oversee the design of the audit; to review all cases of fetal and neonatal loss; and to contribute to this report. An obstetrician and local midwife co-ordinator (LMC) were identified in every site to act as local organisers. All operators who carried out amniocentesis or CVS in Scotland and all five cytogenetic laboratories participated in the audit (Appendix 2). In order to assist the design of the study, a questionnaire was sent to all operators in Scotland to provide background information on the estimated numbers of procedures, usual techniques and equipment (Appendix 3). In addition, a meeting was held for all operators, LMCs, and representatives from the cytogenetic laboratories to outline the day to day detail of data collection methods. A similar meeting was also held half-way through the year of data collection to discuss interim results and identify any difficulties. At the end of the study, a further questionnaire was sent out to operators to determine if reported practice had changed during the study period. Each procedure was allocated a unique number with a prefix that was exclusive to the site at which it had been performed. A triplicate paper form was used for each procedure and was divided into three parts (Appendix 4). Each part contained a copy of the audit number. The first part contained patient identifiable data and was retained at the site where the procedure was performed. The second part contained non-identifiable information about the woman, the indication and the technique used for that procedure. One copy of the second part was filed in the patient’s notes, a copy was sent to the project co-ordinator and a copy was sent with the specimen to the cytogenetic laboratory. If a sample arrived at a laboratory without an accompanying form, the laboratory contacted the LMC and project co-ordinator to pursue the data. After the pregnancy ended, the final part of the form was completed. One copy was filed in the patient’s notes and a copy sent to the project co-ordinator. For any pregnancy which sustained a loss (miscarriage, stillbirth or neonatal death), detailed information was obtained from the LMC using the pregnancy and neonatal loss form (Appendix 5). Data were entered by the project co-ordinator into a database (MS Access 2003, Appendix 6) which was used for data storage and analysis. The project co-ordinator was notified two weeks after the estimated date of delivery (EDD), by which time outcome data should have been returned to the project co-ordinator by the LMC. The project co-ordinator collated and analysed all data, and provided support for laboratory staff and for obstetric and midwife contacts within the maternity sites. Denominator data for births and information on pregnancy losses were obtained from the Information Services Division (ISD) of NHS Scotland7,8.

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As an audit of existing practice, formal ethical approval was not required and this was confirmed by the Scotland A Research Ethics Committee. The Caldicott Guardian in every NHS Board was informed of the study design before the data collection began and no objections were received.

3 Auditable standards

The steering group determined the data to be collected and set the following standards.

3.1 Standards common to both procedures

Standard 1 Consent should be obtained before each procedure.

Standard 2 The technique should include continuous real time ultrasound guidance with up-to-date equipment and colour imaging.

Standard 3 Aseptic technique: probe in a sterile bag, sterile gel and sterile gloves.

Standard 4 Only experienced operators should perform the procedure (performing at least 10 per year) unless training under direct supervision. Trainers should themselves perform at least 50 needle guided procedures each year

3.2 Standards for amniocentesis

Standard 5 Amniocentesis should not be performed before 15 completed weeks.

Standard 6 The outer needle diameter should not be wider than 20 gauge (0.9mm).

Standard 7 The bloody tap rate for fresh blood should be less than 5%.

Standard 8 Success at the first attempt should occur in greater than 95% of procedures.

Standard 9 The procedure related miscarriage rate should not exceed 1%. 3.3 Standards for CVS

Standard 10 CVS should not be performed under 10 weeks.

Standard 11 The procedure related miscarriage rate should not exceed 2%.

3.4 Justification for standards

The justification agreed by the steering group for setting some standards that were not taken entirely from the 2005 RCOG guideline3 is described below. Standard 2 The RCOG guideline from 20002 highlights the need to avoid the cord insertion if a transplacental route is used, although this recommendation is not in the 2005 version3. Nevertheless, it was thought that it was good practice to avoid the cord insertion and free loops of cord. Colour Doppler imaging was, therefore, deemed desirable. In line with recommendations about age of equipment for fetal anomaly scanning9, it was recommended that scan machines should be less than five years old. Standard 3 The 2005 RCOG guideline recommends the use of a sterile bag for the ultrasound probe but does not specifically mention sterile gloves. It does mention that standards should ‘conform to those for any invasive diagnostic radiological procedure’ and it was the opinion of the steering group that this would normally include the use of sterile gloves.

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Standard 5 The 2005 RCOG guideline mentions gestation in two sections. It states that ‘amniocentesis performed before 15 completed weeks is referred to as early’ and that ‘loss rates might be higher’ in comparison with CVS if early amniocentesis is performed. It also reports an associated increased risk of talipes and limb anomalies ‘when early amniocentesis is performed’3. However, the guideline also states that ‘early amniocentesis performed before 14 completed weeks of gestation is not a safe alternative’. There is therefore uncertainty about the gestations between 14 and 14+6 weeks. For the purposes of this audit, it was decided that the standard would be met only if a procedure was performed at 15 completed weeks or more. Standard 6 This standard is a direct quote from the 2005 guideline3. However, it also mentions that, in an experimental comparison of 18, 20 and 22 gauge needles, less leakage occurred with smaller gauge needles. The RCOG guidelines from 1996 and 2000 state that a needle no greater than 22 gauge should be used1,2. Scoring of standards In order to refine the overall analysis of a range of auditable standards, a scoring system was developed. If all technical standards were met at a given site, a score of zero was allocated. Failure to meet certain standards attracted a score of one for each unmet standard. Details of the scoring system are included in the results.

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4 Additional data

Some additional data were collected as recommended by the steering group and are listed below: maternal body mass index (BMI) geographical distribution of patients undergoing the procedures indication for the procedure Fetal Head Circumference or Crown Rump Length at the time of the procedure whether amniocentesis was performed through the placenta needle gauge at CVS and whether a single or double lumen needle was used procedures in twin pregnancies.

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5 Results

5.1 Study population and background information

In 2008, the estimated population of Scotland was 5,168,50010. A total of 57,089 births (live and still) were reported by consultant-led maternity units and in the two midwifery-led units where amniocentesis and CVS procedures were performed from 1st May 2008 to 30th April 2009 (the period of the audit)7. This is slightly fewer than the total births reported by the General Register Office for Scotland (GROS) as there is some under reporting of births to the NHS Information Services Division (ISD) through the Scottish Morbidity Reporting system. In addition, the 1,232 births reported to ISD which occurred at the 20 small midwifery-led units where no amniocentesis or CVS procedures were carried out are excluded, as are births occurring at home. The figure of 57,089 is taken as the denominator for the calculation of the rate of amniocentesis procedures and for the calculation of miscarriage rates. The reporting of miscarriages occurring at less than 15 weeks gestation is unreliable. By means of an email survey of all units in Scotland, it was, however, established that all pregnancy losses after 15 weeks would be managed on a labour ward and, therefore, reported to ISD using the Scottish morbidity record (SMR02). For the purposes of estimating pregnancy loss related to amniocentesis, only losses beyond 15 weeks need be taken into account. During the year of the audit, 244 miscarriages were reported between 15 and 24 weeks7 at the units delivering 57,089 babies. None were reported from units not included in the audit. This gives a rate of 0.43% (95% confidence intervals (CI) 0.38, 0.48).

5.2 Questionnaire results

April 2008 (prior to the audit) Sixty three operators were identified through the Scottish Maternal Fetal Medicine Group. The majority (70%) of the operators were consultant obstetricians with a small number of obstetric associate specialists with staff grades, consultant radiologists and a single sonographer comprising the remainder. Detailed questionnaires were sent to all operators and 54 questionnaires were returned (86%). The responses are summarised in Appendix 7 and important findings are described below. Of the 54 operators that returned questionnaires, 45 (83%) had been performing invasive procedures for more than five years. The majority had never attended a formal training course but had undergone ‘in-house’ training. Seven operators had performed procedures for less than five years and only one of these had been on a formal training course.

Amniocentesis In the two years prior to the study, operators reported performing a median of 45

amniocentesis procedures per year (range 3-188). If the placenta was anterior, the majority of operators (n=41, 76% of the 51

responders to that question) tried to avoid the placenta and at one site all

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operators postponed the procedure rather than go through the placenta (n= 5, 10%). A further five (10%) aimed to go through the placenta if possible.

Most operators (n=45, 84% of 53 responders)) scanned ‘continuously throughout’

the procedure, whilst 11% (n=6) scanned ‘during insertion only’ and 4% (n=2) ‘prior to insertion only’. Only 13 operators (29% of 45 responders) would routinely use colour imaging to check the cord insertion if a transplacental route was being used; all ultrasound machines at all sites did have colour Doppler.

One operator did not wear sterile gloves during amniocentesis. CVS Nineteen of the 54 operators (35%) indicated that they performed CVS procedures

as well as amniocentesis. In the two years prior to the study, operators reported performing a median of eight

procedures per year (range 1-30). All CVS procedures were reported as being performed transabdominally.

Five of the 19 operators (26%) reported not using needle guides during CVS

procedures but if they were used, all were sterile guides. All scan probes were placed in a sterile bag. All operators reported that they wore sterile gloves and used an antiseptic preparation for the skin.

June 2009 (post audit) The same questionnaire was sent to all operators in the month following the end of the audit year to assess any changes of technique as a result of the audit. The response rate was substantially lower than that previously undertaken. Only 25 questionnaires were returned (42%). Several units were using new scan machines obtained during the year of data collection but otherwise there had been no changes in the reported techniques nor had any operator undergone further training.

5.3 Audit results

During the audit period, 2,250 diagnostic invasive procedures were performed by 59 operators, 20 of them performing both amniocentesis and CVS. Data about the indications and techniques for all 2,250 procedures were returned to the project co-ordinator. There were 15 diagnostic procedures reported where the result was not intended to guide management of that pregnancy; these have been removed from the analysis. Eleven of these cases were ‘pre-termination’ procedures where the decision to terminate the pregnancy had already been made due to fetal anomaly identified by ultrasound and sampling was undertaken to obtain karyotype. Four cases were performed as part of post-mortem investigations, intra-uterine death having occurred prior to the procedure. There were 41 procedures performed on women with twins. These procedures have also been removed from the main analysis. During the one year audit period there were, therefore, 2,194 procedures (1,953 amniocentesis and 241 CVS) performed on singleton pregnancies where the result was intended to guide management of that pregnancy.

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In these results, the term ‘site’ is used to denote a location where amniocentesis or CVS was performed. Most sites were consultant-led obstetric units but two sites had recently changed from being a consultant-led to a midwifery-led unit. Operators from the local consultant-led unit visited the midwifery-led unit to perform procedures and this linkage is reflected in Table 1 (site 1 with 13 and site 5 with 14). Table 1 shows the number of deliveries and the number of amniocentesis and CVS procedures carried out at each site during the study period. Delivery numbers were obtained from SMR02 data provided by ISD7. As all sites performed amniocenteses, an amniocentesis rate could be calculated for each (expressed as a percentage of deliveries in the same time period). As CVS was only carried out in a few sites which received referrals from elsewhere, the calculation of a rate is inappropriate. The overall amniocentesis rate during the year of investigation was 3.4% of delivery numbers with a range of 1.5% to 5.3%.

Table 1: Deliveries, amniocenteses and CVS at each site 1/5/08 to 30/4/09:

Site Deliveries7 Amniocenteses

Amniocenteses % of deliveries

(95% confidence intervals)

CVS

1 + 13 4315 226 5.2 (4.6, 6.0) 20 2 4905 247 5.0 (4.4, 5.7) 43 3 3869 85 2.2 (1.8, 2.7) 0 4 208 11 5.3 (2.6, 9.5) 0 5 +14 3248 108 3.3 (2.7, 4.0) 0 6 1188 27 2.3 (1.5, 3.3) 0 7 1315 36 2.7 (1.9, 3.8) 0 8 3264 136 4.1 (3.5, 4.9) 72 9 3295 119 3.6 (3.0, 4.3) 0 10 3872 165 4.3 (3.6, 5.0) 0 11 4943 105 2.1 (1.7, 2.6) 16 12 2218 72 3.2 (2.5, 4.1) 0 15 3347 113 3.4 (2.8, 4.1) 6 16 6831 308 4.5 (4.0, 5.0) 63 17 1170 17 1.5 (0.8, 2.3) 0 18 232 8 3.4 (1.5, 6.8) 0 19 3000 69 2.3 (1.8, 2.9) 0 20 5869 101 1.7 (1.4, 2.1) 21

TOTAL 57089 1953 3.4 (3.3, 3.6) 241 There were 64 procedures at site 1 and 162 at site 13

There were 43 procedures at site 5 and 65 at site 14

Results from the audit of amniocentesis and of CVS procedures are presented separately. Each of the 20 sites has a randomly allocated number or letter and also a colour (shown in some figures). The colour of any one site in the amniocentesis results is different to the colour for that site in the CVS section.

For a site that did not meet a standard for every procedure performed there, there is a cross tabulation with that site’s performance for other relevant standards. The numbers were considered too small to compare miscarriage rates among units.

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5.4 Standards for Amniocentesis

Standard 1: Consent should be obtained before each procedure The 2005 RCOG Guideline states that ‘it is good clinical practice to obtain formal consent’ and that information should be clearly documented and understood by the patient. It does not specify whether consent should be verbal or written 3. In all 1,953 procedures, consent was reported as being obtained; this was written consent in 805 cases (41%). The practice of obtaining consent was usually consistent within sites irrespective of operator. Seven sites obtained written consent for over 90% of procedures and 11 sites obtained verbal consent for over 90% of procedures.

Standard 2: The technique should include continuous real time ultrasound guidance with up-to-date equipment and colour imaging. Thirteen sites met this standard with all procedures performed under continuous ultrasound guidance (65%). In 86% of amniocenteses (n=1669), ultrasound scanning was performed throughout the procedure. Figure 1 shows the distribution of ultrasound technique in relation to amniocentesis at the different sites.

Figure 1: Scanning technique by site n= 1953

PPPPPPPPPPDI

DI

DIDI

DIDI

DITP

TP

TPTP

TP

TPTP

TP

TP

TP

TP

TP

TP

TP

TPTP

TP

TP

TP

TP

0

50

100

150

200

250

300

350

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Site

Nu

mb

er

of

Pro

ced

ure

s

(PP = Prior to Procedure; DI = During Insertion; TP = Throughout Procedure)

At the seven sites which failed to meet this standard for every case, ultrasound scanning was performed only during insertion of the needle in 263 procedures (13%). At five of these sites scanning was reported as being prior to insertion only in 21 procedures (1%). Table 2 shows a comparison of other relevant auditable standards for those sites that did not meet Standard 2 in every case. There is evidence that the number of bloody taps and dry taps (failure to obtain a sample) is increased if continuous ultrasound guidance is not used11,12,13. The results are also compared with the number of uterine entries.

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Table 2: Other auditable standards where Standard 2 was not met in every case

Procedures where Standard 2 not met

Entries ≥2 Bloody tap Dry tap

Site Number of operators

Operator (median)

for amnios n %* n %* n %* n %*

2 8 23 134 54 0 - 2 1 0 -

3 4 17 12 14 0 - 0 - 0 -

4 2 6 1 9 0 - 0 - 0 -

7 2 18 32 89 0 - 0 - 0 -

14 4 15 27 42 2 3 1 2 0 -

15 3 19 71 63 1 1 1 1 1 1

19 3 19 7 10 1 1 1 1 0 -

*Percentage of all amniocenteses at that site Ultrasound machines At the start of the study, there were 34 ultrasound machines used during amniocentesis procedures ranging from less than one year old to eight years old; six machines (18%) were greater than five years old. During the last month of data collection, five sites acquired new machines so that by the end of the study period, all machines used for ultrasound scanning in conjunction with amniocentesis were less than five years old. All machines used throughout the study had colour imaging facility. Figure 2 shows the machine age at the start of the study.

Figure 2: Ages of ultrasound machines used for amniocentesis at start of study n=34

0

50

100

150

200

250

300

350

400

<1 1 2 3 4 5 6 7 8

Age of Machine

Nu

mb

er

of

Pro

ced

ure

s

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Standard 3: Aseptic technique: probe in a sterile bag, sterile gel and sterile gloves Sterile gel is recommended in the 2005 RCOG guideline3. During the study, it became apparent that some units used no gel at all and relied on the antiseptic solution to provide adequate contact between probe and abdomen. Thus, if ‘No’ was the answer to the question ‘Sterile Gel Y/N?’ then it did not necessarily mean that non-sterile gel had been used instead. The question of sterile gel was therefore removed from the analysis. Eleven operators did not use a sterile bag for the ultrasound probe during amniocentesis but did use sterile gloves. One operator did not wear sterile gloves but did use a sterile bag for the probe. In total, seven sites did not meet this standard for every procedure. There were 275 procedures (14%) performed with suboptimal asepsis but no associated cases of chorioamnionitis were reported. In the two cases of pregnancy loss associated with chorioamnionitis, the operator had worn sterile gloves and used a sterile bag for the ultrasound probe. Standard 4: Only experienced operators should perform the procedure (performing at least 10 per year) unless training under direct supervision. Trainers should themselves perform at least 50 needle guided procedures per year Fifty nine operators performed amniocenteses at the 20 sites. One operator left and one was appointed during the study period. The smallest number of procedures carried out by an operator was one; the largest was 119 with a median of 60. Eight sites (40%) failed to meet the standard with one or more operators performing less than 10 procedures during the year. This excludes three operators who performed procedures in more than one site during the study period and whose combined total was greater than 10. Twelve operators (20%) performed fewer than ten procedures in the year. Of these, two also performed CVS but both had a combined amniocentesis and CVS total of less than five procedures. The number of procedures performed by each operator is illustrated in figures 3 and 4. There were a total of 60 (3%) amniocenteses undertaken by operators who performed less than 10 procedures during the year (Figure 3).

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Figure 3: Number of amniocentesis per operator per site n= 1953

0

20

40

60

80

100

120

140

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Site

Nu

mb

er

**

#

#

∆

∆

*, #, ∆ = three operators who worked at more than one site. The minimum number of 10 procedures per year was taken from the 2005 guideline3 but it is admitted in that guideline that this figure is not based on robust evidence. The 1996 version of the RCOG guideline1 suggested 20 as a minimum annual figure and the 2000 version2 suggested a minimum of 30. The guideline published in 2010, after the completion of this audit, also suggests a minimum number of ‘thirty ultrasound guided invasive procedures’ per year4. Figure 4 illustrates the number of operators achieving these numbers for amniocenteses. Considering the uncertainty as to the ideal figure, the data were also analysed with a minimum standard of 30 procedures per year. Of the 59 operators who performed amniocentesis, 34 operators (58%) working at 15 sites performed fewer than 30 amniocentesis procedures per annum. Of these 34 operators, six also performed CVS. When total numbers of procedures for both CVS and amniocentesis are combined, 33 operators (56%) still performed fewer than 30 procedures each within the year of audit. Figure 4: Distribution of operators stratified by number of amniocentesis

0

2

4

6

8

10

12

14

1 - 9

10 -

19

20 -

29

30 -

39

40 -

49

50 -

59

60 -

69

70 -

79

80 -

89

90 -

99

100 - 1

09

110 - 1

19

No. of Amnios

No. of O

per

ators

Table 3 shows the comparison with other associated auditable standards at the eight sites where at least one operator performed less than 10 procedures in the year. The association of higher technical complications with fewer procedures performed is particularly illustrated by sites 4 and 18.

20

Table 3: Other auditable standards where Standard 4 was not met in every case

≥ 2 Entries Bloody or dry tap


Operator (median)

for amnios

Number of operators

<10 amnios

Proceduresby these operators n %* n %*

3 4 17 1 9 0 - 0 -

4 2 6 2 11 2 18 2 18

7 2 18 1 9 0 - 0 -

11 5 19 1 7 1 1 0 -

14 3 22 1 7 0 - 0 -

17 2 9 1 3 0 - 1 6

18 3 3 3 8 2 25 2 25

20 5 24 2 6 0 - 0 - *Percentage of all amniocenteses at that site Procedures performed by trainees During the period of data collection there were 79 amniocentesis procedures (4% of the total) carried out under supervision by six trainees, three of whom were subspecialty trainees. One of the trainees performed procedures in more than one site. There were 20 operators supervising these amniocentesis procedures. The six trainees performed from one to 25 procedures each. Of the 20 supervisors, 10 supervisors working at six sites performed more than 50 procedures during the study period. The range was from 23 to 115 with a median of 20 procedures per supervisor. Standard 5: Amniocentesis should not be performed before 15 completed weeks. In this study the gestation at the time of amniocentesis was determined by one of 3 ways: 1 Using the gestation that was stated by the operator on the audit form at the time

of the procedure. 2 Using the gestation calculated from the expected date of delivery (EDD) stated by

the operator on the audit form at the time of the procedure. 3 Using the gestation calculated from the Head Circumference (HC) measurement

taken at the time of the procedure. The gestation was then calculated by using British Medical Ultrasound Society (BMUS) dating charts14.

As stated by operator Two amniocentesis procedures at different sites were stated by the operator on the audit form as being performed between 14 and 15 weeks gestation.

By stated Estimated Date of Delivery As calculated from the EDD, there were eight cases (0.5%) at six sites performed between 14 and 15 weeks.

21

Head circumference calculation For 1,603 amniocenteses (82%), the HC measurement by ultrasound measurement at the time of the procedure was stated. Using gestation derived from this figure, there were 37 procedures (2%) performed under 15 completed weeks at 13 sites. Two of these procedures at different sites were performed under 14 weeks by gestation derived from HC at two sites. One was noted to have abnormalities on scan (and therefore the HC might have been small due to the abnormality rather than early gestation); in the other there was no reported structural fetal anomaly and the fetal karyotype was normal. By all methods to estimate gestation There were 42 procedures (2.2%) performed under 15 completed weeks at 13 sites. Eight of these procedures were performed as a result of structural fetal anomaly, 22 on maternal request without prior screening and 12 following first trimester screening. Of these 42 cases, eight (19%) were not scanned throughout the procedure, two (4.8%) required two entries and in one of these no specimen was obtained. All were performed with 21 or 22 gauge needles. There were no miscarriages in this group and no cases were found to be associated with talipes at delivery. Amniocentesis after 24 weeks There is no recommended upper limit of gestation for amniocentesis, but it is not often carried out after 24 weeks gestation which is the legal lower limit of viability. In this audit, 26 amniocentesis procedures were carried out between 24 weeks and 34 weeks (1.3% of all diagnostic amniocenteses). The indications are shown in Table 4. In most cases (65%), the indication was the finding of a structural anomaly on ultrasound. The two cases who had a high trisomy risk were screened at 16 and 17 weeks and it is not clear why amniocentesis was carried out so late. In all but three cases (all of which had structural anomalies), the result of the amniocentesis was normal. At birth, a structural anomaly was confirmed in 12 cases. Among the 26 women, there were three stillbirths (one a termination of pregnancy) and four neonatal deaths, all deaths occurring among babies with a structural anomaly.

Table 4: Indications for amniocentesis ≥ 24 weeks gestation (and outcome of those pregnancies) Indication Number Structural anomaly on ultrasound 17 Trisomy risk on screening 2 Growth retardation on ultrasound 3 Maternal age 3 Maternal request 1

22

Standard 6: The outer needle diameter should not be wider than 20 gauge (0.9mm). The needle gauge sizes ranged from 16 to 22 gauge. The majority of operators (78%) used 22 gauge but some used the larger diameter 21 or 20 gauge consistently (Figure 5). A needle gauge wider than 20 gauge was reported in nine procedures (0.5%) over three sites. Relevant features of these cases are shown in Table 5. It might be expected that a wider than average needle would be used if the maternal BMI was very high but this appears not to be the case. All nine procedures using larger gauge needles were performed between 16 and 20 weeks of gestation; one procedure required two uterine entries, but there were no bloody or dry taps. There were no associated pregnancy losses. Figure 5: Needle gauges used in amniocentesis procedures n= 1953

1

8358

72

1514

(18%)(4%)

16 gauge

18 gauge

20 gauge

21 gauge

22 gauge

(78%)

Table 5: Features of 9 cases where large gauge needles were used for amniocentesis


Operator median for amnios

Needle gauge Number of procedures

Median BMI in these cases

3 3 17 16 1 18

13 2 81 18 1 32

16 5 53 18 7 25

23

Standard 7: The bloody tap rate for fresh blood should be less than 5% There were 33 amniocentesis procedures (1.7%) where a fresh bloody tap was reported. Seventeen sites (85%) achieved the auditable standard with a rate of less than 5%; three of these reported rates between 3% and 5%. Table 6 shows the relationship between a bloody tap and other possible factors at the three sites not achieving the standard. Performing a small number of procedures appears to be the most relevant factor.

Table 6: Association of bloody taps with other factors at sites reporting bloody tap rates >5%

Bloody taps

Scanned throughout procedure? ≥ 2 entries Through

placenta

Site Number of Operators

Operator median for amnios n %* n %* n %* n %*

4 2 6 2 18 10 91 1 9 0 -

17 2 9 1 6 17 100 0 - 0 -

18 3 3 2 25 8 100 2 25 0 -

*Percentage of all amniocentesis procedures at that site

There were no fetal losses associated with any of the amniocentesis procedures associated with a fresh bloody tap. Information was also collected on the use of a transplacental route during amniocentesis. Of the 1,953 procedures, 264 (13.5%) were carried out with the operator inserting the needle through the placenta. Eleven of these procedures (4.2%) yielded a fresh blood stained specimen. This compares with fresh blood in 22 cases (1.3%) where the needle did not pass through the placenta.

24

Standard 8: Success at the first attempt should occur in greater than 95% of procedures. This standard was achieved in 1,902 procedures (97%). In 48 procedures (2.5%) two needle entries were required. The maximum number of entries reported was three which occurred in three cases at three sites. Overall, six sites did not meet the standard. All procedures associated with more than one entry used a needle of 20 gauge or thinner. Detailed information is provided in Table 7 which shows possible associations with multiple uterine entries. A failure to scan continuously during needle insertion and performing a small number of procedures appears to be correlated with more than one attempt at needle entry. Table 7: Additional information from units not achieving success in first attempt 95% of the time

≥ 2 uterine entries

Scanned throughout?

Bloody taps Dry taps Site

Number of operators

Operator median for amnios n %* n %* n %* n %*

4 2 6 2 18 10 91 2 18 0 -

11 5 19 11 10 105 100 1 1 0 -

12 3 26 9 13 72 100 2 3 3 4

14 4 15 4 6 38 58 2 3 0 -

18 3 3 2 25 8 100 2 25 0 -

19 4 19 6 7 62 90 3 4 0 -

*Percentage of all amniocenteses carried out at that site

Standard 9: The procedure related miscarriage rate should not exceed 1%. The final outcome of the pregnancy was ascertained in 1,923 (98.5%) of the 1,953 amniocenteses. Thirty women left Scotland before delivery, but in 21 of these cases the pregnancy was known to be continuing at 24 weeks gestation. Information about miscarriage rates is therefore available for all except nine procedures. Also removed from the equation to calculate miscarriage rates, were 26 women on whom amniocentesis was carried out after 24 weeks and 115 pregnancies which were terminated before 24 weeks (usually for fetal anomaly). Therefore there were 1,803 continuing pregnancies after amniocentesis before 24 weeks in which the expectation was of a normal outcome. Among these, there were 19 spontaneous miscarriages. This gives a crude miscarriage rate of 1.05% (CI 0.63, 1.65). Miscarriages can also be expressed as a corrected rate, which excludes pregnancies where a fetal anomaly was recorded. There were 13 miscarriages without fetal anomaly among the 1,803 women, giving a corrected miscarriage rate of 0.72% (CI 0.38, 1.23).

25

This can be compared with the earlier described rate of all reported miscarriages between 15 and 24 weeks in Scotland for the same time period of the audit, which was 0.43% (CI 0.38, 0.48)7. This information is summarised in Table 8. Table 8: Calculation of amniocentesis procedure related pregnancy loss <24 weeks

Total amniocenteses 1,953 Follow-up to 24 weeks complete 1,944 Amniocentesis performed after 24 weeks 26 Pregnancy terminated before 24 weeks 115 Normal outcome of pregnancy anticipated 1803 Spontaneous miscarriages , 15 – 24 weeks 19 (1.05%)*

Corrected spontaneous miscarriages,15-24 weeks (excluding fetal anomalies)

13 (0.72%)*

Scottish spontaneous miscarriages, 15–24 weeks7 244 (0.43%)+

*Percentage of 1803 with normal outcome anticipated +Percentage of 57,089 deliveries in Scottish population Table 9 shows the time interval between amniocentesis and miscarriage. Among both crude and corrected miscarriages, approximately half occurred within 14 days of the procedure. Table 9: Interval between amniocentesis and miscarriage; crude and corrected with rates

Crude Corrected Time after procedure n %* n %*

<14 days 10 0.55 6 0.33

14 - 28 days 6 0.33 5 0.28

>28 days <24 weeks 3 0.17 2 0.11

All 19 1.05 13 0.72

*Percentage of 1803 pregnancies with normal outcome anticipated The assessment of standards 1–8 (described above) identified areas where techniques did not adhere to guidelines. To determine if there was an association between these deficiencies and subsequent miscarriage, details of the technique used in the 13 cases of spontaneous miscarriage were explored. The results are shown in Table 10. No such association was apparent in these small numbers.

26

Table 10: Details of amniocentesis procedures associated with miscarriage without anomaly

Case Loss Scan technique

Gestation at procedure*

Needle gauge

Specimen Uterine entries

1 <14 days Throughout procedure

19 22 Old blood staining

1


18 22 Clear liquor 1









7 14 - 28 days Throughout procedure



17 22 Old blood staining

1



10 14 - 28 days During insertion only




12 >28 days <24 weeks

During insertion only


13 >28 days <24 weeks

Throughout procedure


*(lowest gestation for each case by the various methods of calculation used) Spontaneous losses between 24 weeks and 28 days after delivery Excluding the pregnancies that miscarried (19) or were terminated (115) and those lost to follow up after 24 weeks (30), but including those pregnancies on whom an amniocentesis was performed after 24 weeks gestation, there were 1,789 pregnancies that continued after 24 weeks. Among these there were 21 stillbirths, seven early neonatal deaths (≤ 7days) and one late neonatal death (7-28 days). The perinatal mortality rate was, therefore, 15.7 (CI 10.4, 22.6) per 1,000 births (28/1789). In 2008, the overall Scottish perinatal mortality rate was 7.4 per 1,000 births (CI 6.7, 8.1)15. Eleven of the stillbirths and two of the neonatal deaths were not associated with a fetal anomaly and no particular pattern for these losses was apparent. This information is summarised in Table 11.

27

Table 11: Stillbirths and neonatal deaths following amniocentesis

All cases No anomaly

n %* n %*

Stillbirth (>24 weeks)

21 1.2 11 0.6

Early NND (≤ 7days) 7 0.4 1 0.1

Late NND (>7 < 28 days)

1 0.1 1 0.1

Totals 29 1.6 13 0.7

*Percentage of all 1789 pregnancies continuing after 24 weeks Premature rupture of the membranes Among the 1,789 women undergoing amniocentesis whose pregnancy continued after 24 weeks, rupture of membranes occurred before 37 weeks gestation in 33 pregnancies (1.8%). There was a congenital anomaly in five of these cases. There were no stillbirths or neonatal deaths among the remaining 28. The gestation at which amniocentesis was performed in these cases ranged from 14+4 to 20+3 (based on stated EDD) with a median of 17 weeks. Figure 6 shows the relationship between the gestation at rupture of membranes and gestation at delivery.

Figure 6: Gestation of membrane rupture and gestation at delivery in days

100

120

140

160

180

200

220

240

260

280

140 160 180 200 220 240 260 280

Gestation at Delivery

Ges

tati

on

at

RO

M

28

5.5 Summary of compliance with amniocentesis standards

The overall compliance with the agreed standards is summarised here in two ways. Firstly, in Table 12, the distribution of standards not met for every case at each site is shown. Four sites (1, 8, 9 and 10) met every standard for every case.

Table 12: Overall performance of each site

Site Overall compliance with the agreed standards at each site 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

1. Consent

2. Scan technique x x x x x x x x

3. Asepsis x x x x x x x

4. >10 amnio/ operator x x x x x x x x

5. ≥15 weeks x x x x x x

6. Needle <20g size x x x

7. Bloody tap <5% x x x

8. 1st attempt >95% x x x x x x

Totals 0 1 3 5 2 1 2 0 0 0 3 3 3 4 2 1 3 4 3 1

x = standard not met Secondly, in an attempt to determine how often a standard had not been met, a scoring system was developed as shown in Table 13. For any one procedure, the higher the score, the more standards that had not been met. A score of zero was achieved in 79% of all procedures with a range from 8% to 99% between sites. The scores for all amniocentesis procedures are shown in Table 14 and the scores from individual sites are in Table 15. Table 13: Technique scoring system

Technique Score

Asepsis No skin preparation 1 No sterile gloves 2

Uterine entries 1 0 2 1 3 2

Scan technique Continuous 0 During insertion only 1 Prior to insertion only 2

Specimen Clear 0 Fresh blood 1 Dry tap 2

29

Table 14: Scores for audit standards on all amniocentesis procedures

Total Score n %*

0 1537 79 1 331 17 2 39 2 3 5 0.3 4 6 0.3

*Percentage of all 1953 procedures Table 15: Scores for audited standards at individual sites

Score 0 Score 1 Score 2 Score 3 Score 4 Site

n %* n %* n %* n %* n %*

1 61 95.3 1 1.6 0 - 2 3.1 0 -

2 111 44.9 124 50.2 12 4.9 0 - 0 -

3 69 81.2 9 10.6 7 8.2 0 - 0 -

4 6 54.5 4 36.4 0 - 1 9.1 0 -

5 42 97.7 1 2.3 0 - 0 - 0 -

6 26 96.3 1 3.7 0 - 0 - 0 -

7 3 8.3 33 91.7 0 - 0 - 0 -

8 135 99.3 0 - 1 0.7 0 - 0 -

9 117 98.3 2 1.7 0 - 0 - 0 -

10 163 98.8 2 1.2 0 - 0 - 0 -

11 94 89.6 10 9.4 1 0.9 0 - 0 -

12 42 58.3 23 31.9 3 4.2 0 - 4 5.6

13 156 96.3 5 3.1 1 0.6 0 - 0 -

14 35 53.8 24 36.9 6 9.2 0 - 0 -

15 41 36.3 69 61.1 1 0.9 1 0.9 1 0.9

16 296 96.1 11 3.6 1 0.3 0 - 0 -

17 16 94.1 1 5.9 0 - 0 - 0 -

18 5 62.5 2 25.0 0 - 1 12.5 0 -

19 56 81.2 8 11.6 4 5.8 0 - 1 1.4

20 98 97.0 1 1.0 2 2.0 0 - 0 - *Percentage of all amniocentesis procedures at each site

30

5.6 Additional information for amniocentesis

5.6.1 Maternal Body Mass Index The maternal BMI was recorded in 1,919 of the audit forms (98%).The median BMI was 25 with a range from 15 to 60; 31 women (1.6%) had a BMI over 40. Table 16 shows the relationship between BMI and the procedure. There was a clear tendency towards more technical difficulties with rising BMI. When women were grouped into two categories, BMI 30 or under and BMI over 30, there was a significantly higher rate of multiple uterine entries (p=0.010, Fisher’s exact test) and of bloody taps (p=0.005) among those with a higher BMI. The higher rate of dry taps (p=0.759) and of corrected miscarriages (p=0.116) was not significant, possibly because of the small number of these complications. Table 16: Body mass index and problems with amniocentesis

≥ 2 uterine entries Bloody taps Dry taps* Corrected

miscarriages BMI Number of procedures

n %* n %* n %* n %*

<18 5 0 - 0 - 0 - 0 -

18 to 24 903 18 2.0 9 1.0 4 0.4 6 0.7

25 to 30 699 17 2.4 13 1.8 3 0.4 2 0.3

31 to 34 175 11 6.3 7 4.0 0 - 0 -

35 to 40 106 4 3.8 5 4.7 1 0.9 3 2.8

>40 31 0 - 0 - 0 - 1 3.2

All 1919 50 2.6+ 34 1.8+ 8 0.4 12 0.6

*Percentage of women with specified BMI undergoing amniocentesis +Rate for multiple uterine entries and for bloody taps significantly higher (Fisher’s exact test) among those with higher BMI; see text for details. 5.6.2 National distribution The geographical distribution of the addresses of women undergoing amniocentesis is shown in Appendix 9. The purpose was to assess whether there were any obvious trends in access to the techniques. However, the distribution simply appears to reflect the population distribution of Scotland. There is a suggestion that women are more likely to undergo amniocentesis the nearer they live to a site undertaking the procedure. There are some striking exceptions to this (notably Shetland) but with very small populations, one or two procedures in a given year can create a misleadingly high rate. 5.6.3 Indications for the procedure A range of screening tests may result in an offer to perform amniocentesis to provide definitive information, usually about the fetal karyotype. In Scotland, the most frequent screening procedure was the serum ‘double test’ for AFP and human chorionic gonadotrophin (HCG) performed between 15 and 20 weeks gestation. CUBS at 11-14 weeks gestation was becoming more available during the study

31

period. Amniocentesis may also be offered in some cases where fetal anomaly is suspected on ultrasound scan. The distribution of these indications for all 1,953 amniocentesis procedures is shown in Figure 7. Figure 8 shows the condition for which the screening test suggested a higher chance and the test used to identify that risk for the 1,318 procedures carried out as a result of screening. The majority of procedures (60%) were performed as a result of the double test and most frequently as a result of increased chance of trisomy 21.

Figure 7: Indications leading to amniocentesis n= 1953

142191440

5

1175 Double Test

CUBs

Double Test HCG/AFP CUBS Combined ultrasound and biochemical screening: NT/ PAPP-A/HCG Fetal Anomaly Structural anomaly from ultrasound imaging AWS Amniocentesis without a screening test

Figure 8: Screening tests with identified risks leading to amniocentesis n= 1318

1095

81

1381

3

T21 by Double Test

T18 by Double Test

T21 by CUBs

T18 CUBs

T13 by CUBs

(84%)

(10%)(6%)

Trisomy 21 (T21), Trisomy 18 and Trisomy 13 are all chromosomal abnormalities whose chance of occurring can be estimated by a screening test

Fetal Anomaly

AWS

Other

(60%)

(23%) (10%)(7%)

CUBS

CUBS

by CUBS

CUBS

32

When amniocentesis was performed as a result of screening, in just over half of cases (55%, n=1068), an anatomical survey was performed prior to the procedure. Within any one site this practice was fairly constant. Of the remainder, 850 (44%) women at 18 sites were offered an anomaly screening scan at a later date. Thirty five women (2%) at two sites were not offered an anomaly scan at all. Almost a quarter of procedures (23%) were performed without any screening test and where there was no fetal anomaly detected by ultrasonography. The indications for those 440 amniocenteses are shown in Figure 9. A large majority (85%) were carried out purely on the basis of maternal age or request.

Figure 9: Indications for amniocentesis without a screening test n= 440

(7%)

Other(Genetic)

Previous Aneuploidy

Maternalrequest <35 years

Age 35 - 40years

Age >40 years

30 36 (8%)

23 (5%)

206 (47%)

145

(33%)

5.7 Standards for chorionic villus sampling

CVS was performed at only seven sites Standard 1: Consent should be obtained before each procedure In all 241 procedures, consent was reported as being obtained. In 56% (136) of procedures, this was written and was verbal in the remainder. During the study period, one site changed from verbal to written consent.

Standard 2: The technique should include continuous real time ultrasound guidance with up-to-date equipment and colour imaging. Continuous ultrasound scanning technique was used during all 241 CVS procedures and all ultrasound machines had a colour Doppler imaging facility. At the beginning of the study, the age of machine for CVS procedures ranged from less than one year old to eight years old, with three out of the nine machines used for CVS procedures greater than five years old. However, in the last month of procedure data collection, five sites changed to new machines and by the end of the study, all machines were less than five years old.

33

Standard 3: Aseptic technique: probe in a sterile bag, sterile gel and sterile gloves A sterile bag was used for the probe at all but one site at which 20 (8%) procedures were carried out. All of the operators recorded wearing sterile gloves and all CVS procedures were carried out with the use of a sterile gel. No cases of chorioamnionitis were reported following CVS. Standard 4: Only experienced operators should perform the procedure (at least 10 per year) unless training under direct supervision. Trainers should themselves perform at least 50 needle guided procedures per year All of the 20 operators performing CVS carried out at least one amniocentesis during the study period. Operators carried out between one and 27 CVS procedures with a median of 14. Nine operators (45%) performed less than 10 CVS procedures during the year of data collection. Two of these operators either left or were appointed to their post during the study period. Five of the seven sites failed to meet the standard with one or more operator performing less than 10 procedures during the year. There were a total of 41 CVS (17%) undertaken by operators who performed less than 10 invasive procedures during the year. Figure 10 shows a comparison of the number of CVS procedures carried out by operators in the seven sites while Figure 11 shows the distribution of operators by numbers of procedures performed. There were no CVS carried out by trainees.

Figure 10: Number of CVS procedures by each operator and at each unit. n= 241

0

5

10

15

20

25

30

. . . . . . . . . . . . . . . . . . . .

A B C D E F G

Site

Nu

mb

er o

f P

roce

du

res

Note: the colours are different from those used in the amniocentesis section

34

Figure 11: Number of CVS performed by operators

0

1

2

3

4

5

6

1- 4 5-

9

10 -

14

15 -

19

20 -

24

25 -

29

No. CVS

No

. O

per

ato

rs

No standard was audited for the number of uterine entries required to obtain a CVS, but this information was collected and is described here as it could be a measure of experience in performing CVS. In fact, 224 (93%) procedures were completed with one uterine entry and 17 (7%) required two or more entries; one of these was carried out with a double lumen needle. Further information on needle lumens is provided below. Standard 10: CVS should not be performed under 10 weeks. As for amniocentesis, the gestation at the time of CVS was established in three ways.

1 Using the gestation that was stated by the operator on the audit form at the time

of the procedure. 2 Using the gestation calculated from the EDD stated by the operator on the audit

form at the time of the procedure. 3 Using the CRL or HC measurement taken at the time of the procedure with

gestation calculated using BMUS Fetal size and dating charts14. One of these measurements was provided for 210 CVS procedures (87%). Using any of these methods to determine gestation, no CVS procedures were performed under 10 weeks. There were 27 CVS procedures performed after 14 weeks, 15 of them between 14 and 15 weeks with the remainder spread up to 24 weeks. The indications are summarised in Table 17. The CVS result confirmed a chromosomal anomaly in nine cases; two had a genetic abnormality; 16 were normal. Half (14) of the pregnancies were terminated; there was a normal outcome in twelve pregnancies and one neonatal death.

35

Table 17: CVS performed after 14 weeks gestation

Indication NumberRaised trisomy risk 7 Genetic 4 Increased nuchal translucency on ultrasound 7 Structural anomaly on ultrasound 8 Maternal age 1

Standard 11: The procedure related miscarriage rate should not exceed 2% Of 241 CVS procedures, information about the final outcome of pregnancy was returned for 238 procedures (98.7%) with three cases lost to follow up. Twenty nine CVS were performed after 24 weeks and 79 pregnancies were terminated before 24 weeks. There were, therefore, 130 CVS procedures performed under 24 weeks where the pregnancy continued and the outcome of the pregnancy was known. Ten of these pregnancies miscarried spontaneously, giving a crude miscarriage rate of 7.69% (CI 3.69, 14.15). A ‘corrected’ rate can be calculated by excluding the seven spontaneous miscarriages with a fetal abnormality. This rate was 2.31% (CI 0.48, 6.74), marginally above the recommended maximum of 2%. As previously discussed, the equivalent miscarriage rate among the whole population is not accurately known. The time interval between procedure and miscarriage (14 days, 14-28 days and 28 days) is summarised in Table 18. Although the numbers are very small, the risk of miscarriage appears to continue beyond 14 days after the procedure. Table 18: Crude and corrected miscarriages at different intervals after CVS

Crude Corrected Time after procedure n %* n %*

<14 days 3 2.3 0 -

14 - 28 days 4 3.1 1 0.8

>28 days <24 weeks

3 2.3 2 1.5

Total 10 7.7 3 2.3

*Percentage of 130 continuing pregnancies after CVS

36

Table 19 shows the details of the procedures associated with miscarriage where there was no abnormality. All three procedures appear to have been uneventful and followed the guideline recommendations. Table 19: Details of CVS procedures for ‘corrected’ miscarriages

Case Loss Gestation at CVS

Needle gauge

Double lumen?

Uterine entries

1 14–28 days 10 18 No One

2 ≥ 28 days <24 weeks 11 18 No One

3 ≥ 28 days <24 weeks 11 18 No One In total, 149 pregnancies continued beyond 24 weeks and had adequate follow up information. This includes 29 who had a CVS after 24 weeks but excludes 79 terminated pregnancies, 10 spontaneous miscarriages and three lost to follow up. There were no stillbirths, but there were two neonatal deaths (one early and one late) both of which were associated with congenital anomaly. The perinatal mortality rate among pregnancies undergoing CVS was, therefore, 6.7 per 1,000 births (CI 0.2, 37.4). This compares to the overall Scottish perinatal mortality rate in 2008 of 7.4/1,000 (CI 6.7, 7.4)15 and the rate following amniocentesis of 15.7/1,000 (CI 10.4, 22.6). 5.8 Additional information for chorionic villus sampling

5.8.1 Maternal BMI BMI measurements were provided in 227 cases (94%). The median BMI was 24 with a range from 16 to 43. There was a tendency for women undergoing CVS to have a lower BMI than those undergoing amniocentesis. As shown in Table 20 there appeared to be a trend toward increased number of uterine entries with increasing BMI, however this was not statistically significant (p=0.093, Fisher’s exact test for those with BMI 30 or under and over 30). There were too few corrected miscarriages for analysis.

Table 20: BMI and problems with CVS procedures

≥ 2 entries*

BMI Procedures n %*

<18 3 0 -

18 to 24 112 7 6.3

25 to 30 89 7 7.9

31 to 34 16 4 25.0

35 to 40 6 0 -

> 40 1 0 -

All 227 17 7.5

* Percentage of women with specified BMI undergoing CVS

37

5.8.2 National distribution Appendix 9 shows the geographical distribution of the postal codes of women undergoing CVS which, as for amniocentesis, was included in an attempt to determine if there were any obvious problems with access to CVS. The small numbers mean that no particular pattern is discernible. 5.8.3 Indications for CVS procedures Figures 12, 13 and 14 describe the indications for CVS. Screening in early pregnancy is not well established and the majority of CVS procedures (52%) were performed without a prior screening test, whether biochemical or ultrasound scanning which might suggest fetal anomaly (including increased nuchal translucency). Figure 12: Indications leading to CVS n= 241

127

9121

2

WithoutScreening

Fetal Anomaly

CUBs

Double Test

(52%)

(38%)(9%)

(1%)

CUBS

Double Test HCG/AFP CUBS Combined ultrasound and biochemical screening: NT/ PAPP-A / HCG Fetal Anomaly Structural anomaly on scan including increased NT The indications for CVS among those 127 women who did not have a prior screening test are shown in Figure 13. Those classified as “other” (which was the largest group) mostly underwent CVS for molecular genetic analysis; this included genetic conditions such as cystic fibrosis, muscular dystrophy, haemoglobinopathies and Fragile X.

38

Figure 13: Indications for CVS among those without a prior screening test n=127

Age >40 years

(7%) Age 35 - 40 years 9

In 23 cases (9%), CVS was performed as the result of a risk identified by a screening test risk, usually CUBS. The risks identified are illustrated in Figure 14.

Figure 14: Screening tests resulting in CVS procedures n= 23

2

19

1 1

T21 by DoubleTest

T21 by CUBS

T18 by CUBS

T13 by CUBS

(83%)

(4%) (4%) (9%)

Trisomy 21 (T21), Trisomy 18 and Trisomy13 are all chromosomal abnormalities whose chance of occurring can be estimated by a screening test

26 (20%)

Maternal request<35 years

68 2 Previous 22 Aneuploidy

Other / Genetic

(17%)

) (54%

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5.8.4 Needles used for CVS The RCOG guideline gives no recommendation about the needle to be used for CVS sampling. Single lumen needles have the advantage of a larger internal diameter and can obtain a larger specimen. If however, insufficient tissue is obtained during the first attempt, the whole needle needs to be re-inserted. A double lumen needle avoids the need for re-insertion as a thinner inner needle can be passed into the placenta through the outer needle. A thinner needle, however, may not aspirate an adequate sample. An 18 gauge needle was used for 230 (95%) procedures, 20 gauge for two cases (0.8%) and 22 gauge for nine cases (4%). Of those that used an 18 gauge needle, 188 (78%) were single lumen and 42 (17%) were double lumen. All three ‘corrected’ miscarriages occurred after procedures that used an 18 gauge single lumen needle with a single entry.

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6 Twin pregnancies

Twenty-two twin pregnancies underwent purely diagnostic procedures at eight sites. This does not include diagnostic samples taken at the time of interventions, for example, twin to twin transfusion or as part of selective feticide. There were 21 amniocentesis procedures and one CVS, involving 41 fetuses. Following analysis, it was felt by the steering group that the procedure numbers were too small for comment.

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7 Discussion

The standards used for this national audit were based on guidelines published by the RCOG 4 and were agreed by consensus of the study’s steering group. All units and all operators carrying out these procedures throughout Scotland participated fully throughout the year of the study. Of the 2,250 diagnostic amniocentesis and CVS procedures carried out during the year, 56 were excluded from the study as they were not performed for purely diagnostic reasons and/or were not intended to guide the management or were not singleton pregnancies. Information was obtained about the technique for all 2,194 remaining procedures (1,953 amniocenteses and 241 CVS) but 33 (30 amniocenteses and 3 CVS) women were lost to final follow up. Of these, 22 were known to have pregnancies which continued beyond 24 weeks gestation. As the key factor affecting pregnancy outcome is the miscarriage rate, knowledge that pregnancy continued past 24 weeks is important. Collection and analysis of data in this study was, therefore very thorough and provides robust information. Miscarriage rates can appear falsely low if incomplete data are obtained as pregnancy loss is particularly likely to have occurred among cases that prove difficult to follow up16. There was a high level of compliance with the standards for both amniocenteses and CVS. Perhaps the most important standard of all, the corrected miscarriage rate (excluding pregnancies in which a fetal anomaly was recognised) was, for both amniocentesis and CVS, within acceptable limits at 0.72%(CI 0.38, 1.23) and 2.31% (CI 0.48, 6.74) respectively. The method used to establish miscarriage rates with crude and corrected figures and subdivision into <14 days, 14-28 days and 28 days to 24 weeks was adopted in line with the CVS audit of the West Midlands17. Among CVS procedures in this Scottish audit, there were no losses within 14 days of the procedure which compares with 0.6% in the West Midlands study. For all losses under 24 weeks in this study the rate was 2.31% which compares with 2.9% in the West Midlands Study of 200717. The customised scoring system devised for this study for amniocentesis technique also provides evidence that the service in general is good. Over 97% of procedures achieved compliance with at least 10 out of 11 standards. Some areas of concern were, however, identified. Outside of central Scotland, the country is relatively sparsely populated and some consultant-led maternity units have a small number of births; two have less than 500 births each year and a further three only a little over 1,000. During the audit period, all 18 consultant-led units did, however, provide amniocentesis, which was also carried out at two midwifery-led units by visiting specialists. There were several units with many operators who individually performed a small number of procedures each year. As a result these units failed to achieve compliance with Standard 4 which requires each operator to perform a minimum of 10 procedures per year. Even with the demands of cross cover for absences, it may be difficult to justify more than two operators in many units. Although the numbers were too small for statistical analysis there was a trend for higher complication rates in the smaller units which in general had higher rates of bloody taps and repeat uterine entries.

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The recommended minimum number of procedures to be performed annually has varied between 10 and 30 procedures in each of the three versions of the RCOG guideline available prior to this audit 1,2,3. Since completion of the audit, a further updated guideline has been published4 which recommends that a minimum of 30 ultrasound guided invasive procedures should be performed annually by each operator. This appears to apply to both procedures combined. Fewer than half of the operators in Scotland (26 out of 59) undertook 30 or more of both procedures combined in the year of the audit. There were also some aspects of technique which did not achieve compliance with the standards and on some occasions techniques were well outside that which is considered optimal. It is difficult, for example, to understand the justification for using needles of 18 or even 16 gauge for diagnostic amniocentesis. Two cases of amniocentesis appear to have been performed for an indication of elevated maternal serum alphafetoprotein (MSAFP). This seems an anachronism, particularly as the BMI of the women in whom the test was performed was not elevated and adequate scan quality should have been possible. The RCOG guidelines of 1996 and 20002,3

stated that amniocentesis for an elevated MSAFP was no longer recommended. Maternal age alone is a contentious indication for amniocentesis and may be one of the reasons for the substantial variation in the rates of amniocentesis in different units, which ranged from 1.5% to 5.3% of births. No additional complications or other unexpected findings were revealed in this study. Relatively small numbers make it difficult to draw firm conclusions but the incidence of chorioamnionitis and of premature rupture of membranes was unremarkable. Although the perinatal mortality rate among women undergoing amniocentesis or CVS was approximately twice that of the Scottish population, this is unsurprising in a relatively high risk group of women. There were fewer standards set for first trimester CVS. In general, the technical standards for CVS were met to a high degree with 5 of the 6 standards being met for every procedure. As for amniocentesis, however, there were numerous operators providing the service and many of these undertook very few procedures. Units with more operators performing fewer procedures experienced higher rates of additional uterine entries. There is no clear evidence from which to recommend the use of double or single lumen needle and although only a few procedures were performed with very thin needles, it is perhaps surprising that villi were obtained with a 22 gauge needle and there were no failures of culture. Recommendations for actions based on this audit are included in this report.

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8 Conclusions

This audit has shown that, in general, amniocentesis and CVS are safely performed in Scotland with a high level of compliance with standards. In a small proportion of amniocentesis and CVS procedures the technique could be improved. The use of continuous ultrasound guidance, aseptic technique and appropriately sized needles should be the easiest to address. The key finding that should be considered by service providers is that too many separate individuals are undertaking both of these procedures. As with many procedures requiring a degree of specialist expertise, such prenatal diagnostic tests should be performed by operators with a critical mass of experience that should in turn lead to lower complication rates from the test. These results will be disseminated among the participants of the study. To close the audit cycle, partial or complete re-audit may be necessary.

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9 References

1 Royal College of Obstetricians and Gynaecologists. Amniocentesis and chorionic villus sampling. Green-top guideline no 8. London: Royal College of Obstetricians and Gynaecologists; 1996.

2 Royal College of Obstetricians and Gynaecologists. Amniocentesis and chorionic

villus sampling. Green-top guideline no 8. London: Royal College of Obstetricians and Gynaecologists; 2000.


villus sampling. Green-top guideline no 8. London: Royal College of Obstetricians and Gynaecologists; 2005.


villus sampling. Green-top guideline no 8. 2010 [cited 2010 Oct 18]; Available from: http://www.rcog.org.uk/files/rcog-corp/GT8Amniocentesis0610.pdf

5 Antenatal Screening Wales and NHS Fetal Anomaly Screening Programme.

Amniocentesis and chorionic villus sampling: policy, standards and protocols. 2008 [cited 2010 Oct 19]; Available from: http://www.screeningservices.org.uk/asw/professional/policy/amnio_cvs_policy.pdf

6 NHS Fetal Anomaly Screening Programme. NHS Fetal Anomaly Screening

Programme – screening for Down’s Syndrome: UK NSC policy recommendations 2007-2010: models of best practice [online]. 2008 [cited 2010 Oct 19]; Available from: http://fetalanomaly.screening.nhs.uk/standardsandpolicies

7 Information Services Division (ISD), NHS National Services Scotland. Scottish

Maternity Record (SMR02), Maternity Hospital Discharge Summary.

8 Information Services Division (ISD), NHS National Services Scotland. Births and

babies [online] 2008 [cited 2009 Oct 05]; Available from: http://www.isdscotland.org/isd/1022.html

9 Royal College of Obstetricians and Gynaecologists. Routine ultrasound screening

in pregnancy: protocol, standards and training: supplement to ultrasound screening for fetal abnormalities. Report of the RCOG Working Party [online] 2000 [cited 2010 Oct 19]; Available from: http://www.rcog.org.uk/womens-health/clinical-guidance/ultrasound-screening

10 General Register Office for Scotland. Mid-2008 population estimates Scotland:

population estimates by sex, age and administrative area. 2009 [cited 2009 Aug 21]; Available from: http://www.gro-scotland.gov.uk/files2/stats/gros-mid-2008-population-estimates-scotland-population-estimates-by-sex-age-and-administrative-area/gros-mid-2008-population-estimates-scotland-population-estimates.pdf

11 Crandon AJ, Peel KR. Amniocentesis with and without ultrasound guidance. Br J

Obstet Gynaecol 1979;86(1):1-3.

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http://www.isdscotland.org/isd/1022.html

12 de Crespigny LC, Robinson HP. Amniocentesis: a comparison of ‘monitored’

versus ‘blind’ needle insertion technique. Aust N Z Obstet Gynaecol 1986;26(2):124-8.

13 Romero R, Jeanty P, Reece EA, Grannum P, Bracken M, Berkowitz R, et al.

Sonographically monitored amniocentesis to decrease intraoperative complications. Obstet Gynaecol 1985;65(3):426-30

14 British Medical Ultrasound Society. Fetal size and dating: charts recommended

for clinical obstetric practice [online]. 2009 [cited 2010 Oct 19]; Available from: http://www.bmus.org/policies-guides/pg-fetalmeas.asp

15 Information Services Division (ISD), NHS National Services Scotland. Scottish perinatal

and infant mortality and morbidity report 2008 [online] 2010 [cited 2010 Oct 19]; Available from: http://www.isdscotland.org/isd/3112.html

16 Halliday JL, Lumley J, Sheffield LJ, Robinson HP, Renou P, Carlin JB. Importance of

complete follow-up of spontaneous fetal loss after amniocentesis and chorion villus sampling. Lancet 1992;340(8824):886-90.

17 Tonks A, Wyldes MJ, Kilby M D. Population-defined epidemiological data of first trimester

chorionic villus sampling performed in the West Midlands region of the United Kingdom during 2005. Reproductive Sciences. 2008;15(1 Suppl):152.

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http://www.isdscotland.org/isd/3112.html

Appendices

Appendix 1: Steering group members

Charmaine Bremner Midwife, Project Co-ordinator

Alan Cameron Fetal Medicine Consultant Obstetrician, NHS Greater Glasgow and Clyde, Project Co-Lead

Shona Cowan Consultant Obstetrician, NHS Lothian (formerly sub specialty trainee representative) Penny Hicks Lay Representative

Mark Kilby Professor of Maternal & Fetal Medicine, University of Birmingham & Birmingham Women’s Foundation Trust, Birmingham, Chair of Steering Group

Chris Lennox Clinical Advisor, NHS Quality Improvement Scotland

Leslie Marr Reproductive Health Programme Co-ordinator, NHS Quality Improvement Scotland Norman Smith Consultant Obstetrician, NHS Grampian

Graham Tydeman Consultant Obstetrician NHS Fife, Project Lead

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Appendix 2: Cytogenetic laboratories and maternity units

Cytogenetic Laboratories

Maternity Units

South East Scotland Human Genetic Laboratories, Dundee

Ninewells Hospital, Dundee Perth Royal Infirmary

North Scotland Clinical Genetics Service, Aberdeen

Aberdeen Maternity Unit Dr Gray’s Maternity, Elgin

South East Scotland Regional Genetics Centre, Edinburgh

Simpsons Centre for Reproductive Health St John’s, Howden Forth Park Maternity Hospital, Kirkcaldy Borders General Hospital, Melrose

West Scotland Regional Genetics Service, Yorkhill, Glasgow

Queen Mothers Hospital, Glasgow Princess Royal Maternity, Glasgow Southern General Hospital, Glasgow Royal Alexandra Hospital, Paisley Ayrshire Maternity Western Isles Maternity, Stornoway Inverclyde Hospital, Greenock Cresswell Maternity, Dumfries Stirling and Falkirk Royal Infirmaries Wishaw General Hospital

Inverness Cytogenetics Laboratory Raigmore Hospital, Inverness Caithness General Hospital, Wick

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Appendix 3: Operator’s pre-study questionnaire April 2008

Amniocentesis and CVS Audit, Scotland

************* Please use a separate form for each person who does CVS/ amnio in your unit **************

About You Name/ Grade ……………………………………… obstetrician / midwife / sonographer / radiologist / other

Contact email …………………………………………………………………………..………………………………

1. Do you perform Amniocentesis? YES / NO

2. Do you perform CVS? YES / NO

3. Name of your unit?……………………………………………………………………………………………………

4. How long have you been performing these procedures? 1 2 3 4 5 >5yrs

5. Approx how many amniocentesis have you performed in the last 2 years? ………………………………….

6. Approx how many CVS have you performed in the last 2 years? ……………………………………………..

7. Have you been on a formal training course to perform amniocentesis? YES / NO

If YES please specify………………………………………………….……………………………………………

8. Have you been on a formal training course to perform CVS? YES / NO

If YES please specify………………………………………………….……………………………………………

Your Technique Both procedures

10. Obtain written consent? YES / NO

11. Use antiseptic on the skin YES / NO

12. Wear sterile gloves YES / NO

13. Put the scan probe in a sterile bag YES / NO

14. Use sterile Gel YES / NO

Amniocentesis

15. A detailed scan is performed prior to amniocentesis YES / NO / SOMETIMES

16. When performing amniocentesis do you scan:

prior to insertion of needle only / during insertion only / continuously through procedure / not scan at all

17. If the placenta is anterior do you

avoid it if possible / aim to go through it / postpone / cancel the procedure

18. If you go through the placenta, do you check the position of the cord insertion YES / NO

19. If yes, do you use colour imaging to check cord insertion YES / NO / SOMETIMES

20. Do you have an assistant to withdraw the fluid YES / NO / SOMETIMES

21. If you have an assistant, do they wear sterile gloves YES / NO

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CVS

22 Approach you use (one or both) Transabdominal Transvaginal 23 Needle type single / double lumen single / double lumen 24 Probe in sterile bag YES / NO YES / NO 25 Needle guide YES / NO YES / NO 26 If use a needle guide is it sterile YES / NO YES / NO 27 Wear sterile gloves YES / NO YES / NO 28 Antiseptic prep YES / NO YES / NO 29 Use sterile gel YES / NO YES / NO

About Your Department

30. Who usually performs Amniocentesis? Obstetrician / Midwife / Radiologist / Sonographer / Other (indicate)

If Obstetrician/ Radiologist: Consultant / Associate Specialist / Staff Grade / Other………………………………

31. Who usually performs CVS? Obstetrician / Midwife / Radiologist / Sonographer / Other (indicate)

If Obstetrician/ Radiologist: Consultant / Associate Specialist / Staff Grade / Other………………………………

Ultrasound Machines Used for Amniocentesis / CVS

Machine make and model Age Colour imaging? When due to be replaced

Y / N

Y / N

Y / N

Trainees

32. Does your department train people to perform amniocentesis?

33. if so are your trainees: O+G / Radiology / Midwifery / other…………………….

34. Does your department train people to perform CVS?

35. if so are your trainees: O+G / Radiology / Midwifery / other…………………….

36. How many amniocentesis do your trainees perform per year

37 How many CVS do your trainees perform per year …………………………………………………………

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Appendix 4: Data collection form

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Appendix 5: Pregnancy and neonatal loss form

Audit Prefix Number

Previous Pregnancies

No of previous pregnancies

Please note details of preterm labour, abruption, thrombophilia, congenital abnormality (including chromosomal), cervical surgery Gestation Outcome Details/Any comments re pregnancy and outcome

This Pregnancy

Age

1st Trimester BHCG PAPP-A

If screening: 2nd Trimester HCG AFP

Bleeding pre procedure Y N

Bleeding post procedure Y N

Evidence of in utero infection Y N

IUD before procedure Y N

PROM Y N

Date of PROM

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Pregnancy Outcome

Days from procedure to fetal loss days

Was delivery onset Spontaneous Iatrogenic Surgical

Please give details of delivery:

d Was Post Mortem Performed? Y N

Neonatal Loss Details Neonatal Outcome Gestation at Delivery

Age at death

Reason for death Prematurity / Lethal Congenital / Structural / Infection /

Other (Please comment)

Any other comments

Was Post Mortem Performed? Y N

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Appendix 6: Microsoft Access database collection page

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Appendix 7: Summary data from pre-audit questionnaire

0

5

10

15

20

25

30

35

40

45

Number of operators

>5yrs 5 years 4 years 3 years 1 year 6 months

Years performing invasive procedures

How long have you been performing these procedures?

55

Who performs Amniocentesis / CVS in your unit? (n=54)

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3221

Consulttantobstetrician

Obstetric AssociateSpecialist

Staff GradeObstetrician

Radiologist

Staff Grade MedicalSonographer

Do you perform a detailed scan prior to amniocentesis? (n=54)

346

14Yes

No

Sometimes

Have you been on a formal training course to perform amniocentesis / CVS? (n=54)

12

42

Yes

No

When performing amniocentesis do you scan.. (n=53)

62

45

Prior to insertion ofneedle?

During insertion only?

Continuously throughoutprocedure?

If the placenta is anterior do you.. (n=51)

5

41

5

Aim to gothrough it?

Avoid it ifpossible?

Postponeprocedure?

If yes, do you use colour imaging? (n=45)

13

12

20

Yes

No

Sometimes

If you go through placenta do you check

position of the cord (n=45)

Yes

No

35

Do you place the scan probe in a sterile bag? (n=54)

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6

Yes

No

CVS Needle type. Double or single lumen? (n=19)

5

14

Double

Single

Appendix 8: Additional data collection form for twins

In addition to an individual form for each time the procedure was performed.

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Appendix 9: National distribution of amniocentesis and CVS procedures

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Appendix 10: Abbreviations used

AFP alphafetoprotein AWS amniocentesis without screening test BMI body mass index BMUS British Medical Ultrasound Society CI 95% confidence intervals CRL crown rump length CUBS combined ultrasound and biochemical screening CVS chorionic villus sampling double test AFP and HCG EDD estimated date of delivery HC head circumference HCG human chorionic gonadotrophin ISD Information Services Division LMC local midwife co-ordinator NHS QIS NHS Quality Improvement Scotland NSC National Screening Committee NT nuchal translucency PAPP-A Pregnancy Associated Plasma Protein A RCOG Royal College of Obstetricians and Gynaecologists ROM rupture of membranes SMR02 Scottish Morbidity Record 02

Amniocentesis and Chorionic Villus Sampling in Scotland

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