Umbilical Artery Systolic/Diastolic Ratio and Amniotic Fluid Index in Prediction of Adverse Perinatal Outcome in Term Pregnancies

BACKGROUND: Antenatal fetal surveillance is a field of increasing importance in modern obstetrics. It is based on fetal heart rate monitoring using nonstress test and contraction stress test, ultrasound biometry and amniotic fluid assessment, Doppler blood flow studies of fetal and uteroplacental circulation, and an evaluation of biophysical fetal parameters. The combination of these methods leads to improvements in fetal morbidity and mortality. AIM: The present study aimed to assess the sensitivity, specificity, and positive and negative predictive values of umbilical artery (UA) systolic/diastolic (S/D) ratio, and amniotic fluid index (AFI) in term pregnancies for the prediction of perinatal outcome and their relation with perinatal outcome. METHODS: This study was conducted at a tertiary care hospital on 100 pregnant women where all the term singleton pregnancies (37–42 weeks) admitted in maternity were subjected to color Doppler for UA S/D ratio assessment and AFI estimation. Further, management of patients was done according to color Doppler findings and their relation with perinatal outcome. RESULTS: Out of 100 pregnant women, 68% had AFI >8 (normal), while 32% of women had AFI <8 (abnormal), with the mean AFI being 9.39 ± 2.55 cm, whereas70% had S/D ratio <3 (normal) and 30% of women had S/D ratio >3 (abnormal), with the mean S/D ratio of 2.61 ± 0.450. UA S/D ratio had better performance values (i.e., sensitivity, specificity, and positive and negative predictive value) than AFI in predicting adverse perinatal outcomes. CONCLUSION: AFI and UA S/D ratio are important for predicting low appearance, pulse, grimace, activity, and respiration score, meconium, respiratory complications, and perinatal mortality in high as well as low-risk pregnancy cases. However, UA S/D ratio is a better predictor of perinatal outcome in high-risk pregnancies.