A Study of Fetal Umbilical Artery Flows and Neonatal Outcome in Small for Gestational Age Fetus

This is a longitudinal study of 109 pregnant women over a period of 2 years who attended the antenatal clinics between 30–40 weeks of gestation with a clinical or sonological diagnosis of SGA fetuses without any clinical causes excluding preeclampsia. In the present study, fetal umbilical artery Systolic/Diastolic ratio(S/D), Pulsatility index (PI), resistance index (RI) were studied. Fetuses with elevated S/D ratios were associated with oligohydramnios (P<0.05). Umbilical artery S/D ratio had a sensitivity of 74% and a specificity of 78%in prediction of abnormal NSTs. Only 13% of fetuses with abnormal S/D ratios had birth weight less than 10th percentile. It was significantly associated with caesarean sections (P<0.05). Absent end diastolic flows were associated with poor prognosis and 100%mortality in this study. The resistive index is a sensitive predictor of antenatal factors such as oligohydramnios and non-reassuring fetal cardiac tracings. Fetuses with abnormal RI had abnormal CTG in 52% cases, with a sensitivity of 52% and specificity of 59%. RI is not a good predictor for neonatal outcome measures. Elevated PI with associated sensitivity for prediction of oligohydramnios was 65% and specificity was 76%. It was significantly associated with NICU stay >48 hours (p<0.05). Abnormal PI was associated with non-reassuring fetal heart tracings (p<0.05).