Umbilical Artery Doppler Velocimetry and Its Relation to Perinatal Outcome in Normal and High-Risk Pregnancies

Abstract

BACKGROUND Umbilical artery Doppler waveforms provide an estimate of downstream placental vascular resistance and placental blood flow. We wanted to assess the relation between umbilical artery Doppler velocimetry and perinatal outcome in normal and high-risk pregnancies. METHODS The Doppler Ultrasound was performed on 120 pregnant women between 30 and 32 weeks of gestation. Umbilical artery Doppler indices (S/D ratio and RI) were recorded and its relation was assessed with perinatal outcome parameters and analyzed statistically. RESULTS S/D ratio and RI showed significantly higher values in the high-risk group (4.1, 1.2) as compared to the control group (2.4, 0.58). The mean period of gestation at delivery was 35.28 + 1.85 weeks in high risk group compared to 38.05 + 1.03 weeks in low risk group. Majority of the women (56.6%, n=34) in the control group had spontaneous labour while in the high-risk group, 61.6% (n=37) of women underwent LSCS. The mean birth weight of newborns was lower in the high-risk group (2.48 kg) as compared to the control group (3.02 kg). Average birth weight was significantly lower for fetuses with abnormal Doppler velocimetry (S/D ratio) than for those in the normal Doppler group. In the present study, there was higher admission rate of newborns to the NICU and a greater number of newborns required ventilator support in the high-risk group as compared to the control group. Newborns who had NICU stay and required ventilator support showed abnormal S/D ratio of umbilical artery. There were three perinatal deaths in the high-risk group compared to none in the control group. CONCLUSIONS The results of our study support the use of Doppler umbilical artery waveform analysis as an important foetal well-being investigation which though not necessarily diagnostic has a lot of prognostic value.