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
Aboubakr Elnashar
Interpretation:
• Resistance index: best ability to predict abnormal outcomes (RCOG,2002
Evidence level II)
• Enddiastolic flow
• Systolic/diastolic ratio
• Pulsatility index
• Diastolic average ratio
Aboubakr Elnashar
Doppler indices
Aboubakr Elnashar
• 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.
Aboubakr Elnashar
•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}.
Aboubakr Elnashar
Normal
Absent
Reversed
Aboubakr Elnashar
RED
Aboubakr Elnashar
RED
Aboubakr Elnashar
Absent
Reversed
Aboubakr Elnashar
Advantages:Advantages:
1. In low risk
No benefit on mother or baby (The Cochrane Library, 2003)
Aboubakr Elnashar
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
Aboubakr Elnashar
• 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)
Aboubakr Elnashar
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
Aboubakr Elnashar
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
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