Comparison of Amniotic Fluid Index and Single Deepest Vertical Pocket

Abstract

Background: The best method of estimation of amniotic fluid volume is a matter of ongoing debate. Objectives: To determine the perinatal & maternal outcomes in pregnant patients when the amniotic fluid volume was assessed by the amniotic fluid index (AFI) in comparison to the single deepest vertical pocket (SDVP). Methods: We studied abnormal Cardiotocograph, meconium stained amniotic fluid, birth weight <2.5kg, Apgar score at 5 min <7, cord blood pH <7.2 & necessity for NICU admission as perinatal outcomes. Rate of diagnosis of oligohydramnios, induction of labor for oligohydramnios & mode of delivery were observed in maternal outcomes. Results: Of the 697 pregnant patients recruited, 353 were in the AFI and 344 in the SDVP group. Perinatal outcomes were similar in both. In the AFI group, the number of women diagnosed with oligohydramnios was higher (p = 0.0333) & the rate of induction was also higher (p = 0.003378). Vaginal deliveries were more in the SDVP group. The Receiver Operating Characteristic curves showed statistically significant correlation with NICU stay, birth-weight, and mode of delivery. While an AFI of >5cm and SDVP of >1.9cm had good sensitivity in predicting babies with a birth weight of ≥ 2.5kg and avoiding NICU admissions, an AFI of > 5.8cm and an SDVP of > 1.9 cm had a sensitivity of around 80% in predicting successful vaginal deliveries. Conclusion: The SDVP method has a slight edge over the AFI in terms of lower inductions and higher vaginal deliveries with comparable perinatal outcomes.