Amniotic Fluid Index versus Umbilical Artery Doppler Velocimetry in Prediction of Perinatal Outcome

Aim and Objectives: To assess the sensitivity, specificity, positive and negative predictive values of Amniotic Fluid Index and Umbilical Artery S/D Ratio in the third trimester for the prediction of perinatal outcome and  to compare the performance of both the tests.

Materials and Methods:  It is a prospective study conducted at a tertiary care centre. AFI and Umbilical Artery S/D Ratio was measured every 4 weeks for high risk pregnancy cases beyond 30 weeks period of gestation and perinatal outcome noted.  Results were analyzed by diagnostic tests sensitivity, specificity, positive and negative predictive values.

Result: Amniotic Fluid Index has sensitivity, specificity and positive and negative predictive values of   55 % – 87.5%, 65 % - 75%, 35% - 60%, 70% - 97% in predicting poor perinatal outcome.  Whereas Umbilical artery S/D ratio has sensitivity, specificity and  positive and negative  predictive values of  60 % – 80% , 70 % - 80%, 20% - 80%, 80% - 100% in predicting poor perinatal outcome.

Conclusion: Antepartum foetal surveillance is the cornerstone of management which has been revolutionized by use of Ultrasound. There is a significant association between AFI, Umbilical artery Doppler on perinatal outcome. Both the tests should form an integral part of antepartum fetal surveillance In the present study Umbilical Artery S/D ratio has better performance value than Amniotic Fluid Index in predicting perinatal outcome. Umbilical Artery S/D Ratio is better predictor of perinatal outcome in high risk pregnancies.