Ante-natal doppler assesment

Quite frequently we need to make a doppler assesment of ante-natal patients, whenever abnormal biometry points towards IUGR. A quick check on umbilical artery, see if there is good diastolic flow, and confirm IUGR if you see a diastolic notch and high pulsatility. S/D ratios may be unreliable many a times. But, taking a ratio of MCA and umbilical artery is very sensitive and specific. I would suggest no panic if you only see low S/D ratio in MCA, while uterine and umbilical arteries are fine.

Checklist
1. Umbilical artery
2. MCA
3. Uterine arteries
4. Umbilical vein
5. Ductus venosus

1. S/D Ratio and PI of MCA/Umbilical artery less than 1 signifies IUGR.

2. Diastolic notch or absence of diastolic flow in umbilical arteries signifies adverse outcome.

3. Diastolic notch with high pulsatility index of Uterine arteries signifies uteroplacental insufficiency.

4. Smooth umbilical venous cord flow with peak velocity of 16 cm/sec signifies IUGR.

5. Decreased pulsatility in MCA signifies redistribution of blood flow.

6. Loss of 'M' Pattern in ductus venosus due to absent or reversed 'a' wave.