Preterm Labor

Introdution

24 37

Survival by gestational age among live-born resuscitated infants

In: Creasy, Resnik . Maternal – Fetal Medicine, 2009

Pathophysiology

Ascending intrauterine infections stage I changing flora vagina/cervix, II Microorganism alocated between the amnion and chorion, III intra amniotic infection, IV fetal invation

Infection

Genital * Bacterial vaginosis (BV) * Group B streptococcus * Chlamydia * Mycoplasmas

Intra-uterine * Ascending (from genital tract) * Transplacental (blood-borne) * Transfallopian (intraperitoneal)

* Iatrogenic (invasive procedures)

Extra-uterine * Pyelonephritis * Malaria * Typhoid fever * Pneumonia * Listeria * Asymptomatic bacteriuria

Infections associated with preterm delivery

In:Jane Norman.Preterm labor 2005

Over distension

Multiple

GestationPolyhydramnios

Vascular ( uteroplacental disturbance )

Surgical procedures and intercurrent illness

Pyelonephritis Appendicitis Pneumonia

Cholestasis Amniocentesis

Abnormal uterine cavity

Cervical weakness

Risk Factors Previous preterm delivery or late miscarriage Multiple Gestation Cervical surgery Uterine anomlies Medical condition e.g renal disease Pre-eclampsia & IUGR (spontaneous & iatrogenic)

Diagnosis

History Examination Investigations

History

Ask about pain/contactions–onset – frequency-duration-severity.

Vaginal loss : SROM or PV bleeding Obstetric History

Examination

Maternal pulse – tempreture – respiratory rate.

Uterine tenderness ( abruption – infections) Fetal presentation Speculum : look for blood,discharge,liquor.

Take swaps . Gentle VE

Investigations

FBC Swabs MSU USS for fetal presentation – age Fetal fibronectin TVS if available

Management

Theartend or real Labour (TVS cervical >15mm – Neg fibronectin

assay )>> unlikely to be labour . Admision if high risk & inform neonatal unit Arrange in utero transfer Check fetal presentation by US Steriods

Tocolytic Therapy ex nifidipine ( still prefer to avoid it , because no

improvement in perinatal mortality and morbidity

Liason with senior obstetricians & neonatologists is essential .( 23-26 wks ): Mode, monitoring,intervention during Labor.

Start IV antibiotics if labour confirmed

Prevention

Rx of bacterial Vaginosis Progesterone Cervical cerclage Cervical pessary Reduction of selective number of

pregnancy

Premature of membrane

Definition

Premature rupture of the membranes (PROM) is defined as amniorrhexis (spontaneous rupture of membranes) prior to the onset of labor at any stage of gestation

Incidence

PROM occurs in about 1/3 of preterm deliveries.

1/3 caused with other infections

Cause of PROM(1)

The cause of PROM is not clearly understood, perhaps associated with the follow factors:TraumaSexual intercourse (particularly in the late

gestational weeks) lax of internal os of uterine

Cause of PROM(2)

Vaginal infection due to bacteria, virus, TOXO, CMV, HPV, HSV, et al STDs sexually transmitted diseases play an important role in the cause of PROM, because such infections are more commonly found in women with PROM than in those without PROM

Increased of intra-uterine pressure (such as multiple pregnancy and hydraminios)

Abnormalities in presentation and position

Cause of PROM(3)

Smoking the risk of PROM is at lease doubled in women who smoke during pregnancy

Other factors for PROM include the follow Prior PROM A short cervical length Prior preterm delivery Bleeding in early pregnancy

Manifestation and Diagnosis

Fluid passing through the vagina suddenly, and then small amounts of fluid flow through the vagina intermitently, particularly when the increased of abdorminal pressure (cough, sneeze, et al)

Intermittent urinary leakage is common during pregnancy, especially near term

Increased vaginal secretions in pregnancy Perineal moisture Increased cervical discharge Urinary incontinence Vesicovaginal fistula

May be mistaken for the fluid

Experimental Test(1)

The Nitrazine test uses pH to distinguish amniotic fluid from urine and vaginal secretions, the paper turns dark blue in response to the amniotic fluid

Amniotic fluid is quite alkaline having a pH above 7.0, but vaginal secretions in pregnancy usually have pH values of less 6.0

Experimental Test(2)

The “fern” test : placing a sample on a microscopic slide, air drying, and examining for ferningThe amniotic fluid does fernThe other fluid does not fern

Risk of PROM

Preterm labor: 75% Intrauterine infection(chorioamnionitis, 30-

50% of case)-( maternal fever – abdominal pain –offensive discharge – tachytracia)

Puerperal infection

Fetal and neonatal complications

Fetal and neonatal pneumonia, sepsis Neonatal respiratory distress syndrone Neurologic dysfunction Intracranial hemorrhage Prolapse of umbilical cord Abruptio placenta

Evaluation

The gestational age( LMP, ultrasound and uterus fundal height measurement)

The presence of uterine contractions (abdominal examination) The amount of amniotic fluid (ultrasound) Fetal heart rate (FHR monitor) Fetal maturity (L/S or PG) The likelihood of chorioamnionitis (white blood cell count) The likelihood of prolapse of umbilical cord

Management

If there is an evidence of chorioamnionitis : steroids –deliver – antibiotics

If not : conservation with admission with information neonatal unit – steroids – antibiotics (erythromycin)