Umblical & uterine

artery Doppler

Aboubakr Elnashar

I. Umbilical artery Doppler

Idea:

Umbilical Arterial Flow is normally of low

resistance.

In hypoxic states:

relative placental hypoxia:

reactive VC of umbilical artery:

higher resistance:

decrease in diastolic flow

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Interpretation:

• Resistance index: best ability to predict abnormal outcomes (RCOG,2002

Evidence level II)

• Enddiastolic flow

• Systolic/diastolic ratio

• Pulsatility index

• Diastolic average ratio

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Doppler indices

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• Resistance Index:

In normal pregnancy:

{progressive increase in end-diastolic velocity

{growth& dilatation of the umbilical circulation}:

Resistance index falls.

In fetal growth restriction and/or

preeclampsia:

> 0.72 is outside the normal limits from 26 w.

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•End Diastolic flow

In fetal growth restriction and/or preeclampsia:

is reduced, then

absent (AED) or

reversed (RED) in severe cases

Absent or reversed:

Fetal distress is almost certain:

Immediate BPP or NST or

Delivery may be indicated. Aboubakr Elnashar

•S/D

Should be <3.

Small increases in S/D= 3-5:

chronic intrauterine disease manifest by IUGR.

Not strictly useful:

{1. low sensitivity.

2. Gestation age dependent}.

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Normal

Absent

Reversed

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RED

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RED

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Absent

Reversed

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Advantages:Advantages:

1. In low risk

No benefit on mother or baby (The Cochrane Library, 2003)

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2. In high risk: Reduction of

perinatal morbidity and mortality

number of antenatal admissions

inductions of labor

resources compared with CTG

(Grade A RCOG, 2002; The Cochrane Library, 2003)

Comparing FHR monitoring, FBP and umbilical artery Doppler:

only umbilical artery Doppler had value in predicting poor perinatal

outcomes in SGA

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• Frequency of monitoring in SGA fetuses with normal Doppler:

Once/2w (RCOG, 2002 Evidence level II)

• A 4-week U/S measurement interval was shown to be superior to a 2-week interval, in terms of reducing the false –positive rate (Owen et al,

2001).

• Once/2w (Fortnightly) scans should be undertaken where

1. linear growth velocity is not maintained or

2. AC is below the third centile (IV)

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II.Uterine artery Doppler

• limited use in predicting FGR and

perinatal death (Grade A, RCOG,2002).

• Abnormal uterine artery suggest:

maternal cause for the growth

restriction

• Normal uterine artery Doppler

suggest:

fetal cause Aboubakr Elnashar

UAD: Normal

UAD: notch, decreased diastolic flow

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Prediction of preeclampsia

(Uterine Doppler velocimetry)

• Persistence of a Diastolic

Notch in uterine artery

waveform after 24 w

• Systolic/diastolic ratio >2.6

• RI > 0.58 after 24 weeks.

Systole

Diastole

Aboubakr Elnashar

Aboubakr Elnashar