Comparative Performance of Amniotic Fluid Index and Single Deepest Pocket in Predicting Adverse Perinatal Outcomes in High-Risk Pregnancies

Abstract

Background: Accurate sonographic assessment of amniotic fluid volume is essential in high-risk pregnancy, yet uncertainty persists regarding whether amniotic fluid index or single deepest pocket better predicts adverse neonatal outcome. Objective: To compare the diagnostic agreement, neonatal outcome associations, and predictive performance of AFI and SDP in high-risk pregnancies. Methods: This prospective comparative study included 81 high-risk pregnant women assessed at HBS Hospital, Islamabad, from June to December 2025. AFI and SDP were measured during the same ultrasound examination. Oligohydramnios and polyhydramnios were classified using standard thresholds. Neonatal outcomes included birth weight, 1-minute and 5-minute Apgar scores, NICU admission, and a composite adverse perinatal outcome defined as NICU admission, 5-minute Apgar score <7, or birth weight <2500 g. Agreement, correlations, and diagnostic performance measures were analyzed. Results: Mean AFI was 14.2 ± 6.8 cm and mean SDP was 4.6 ± 1.9 cm. Agreement between methods was moderate (κ=0.61; 95% CI 0.48-0.74), with discordance in 18.5% of cases. AFI showed stronger correlations than SDP with 1-minute Apgar (r=0.52 vs 0.31), 5-minute Apgar (r=0.48 vs 0.28), birth weight (r=0.41 vs 0.22), and NICU admission (r=-0.44 vs -0.28). AFI demonstrated higher sensitivity for the composite adverse outcome (78.9% vs 63.2%), whereas SDP showed higher specificity (91.5% vs 82.5%). Conclusion: AFI more reliably identified neonatal compromise in high-risk pregnancies, while SDP provided valuable confirmatory specificity, particularly in discordant or borderline cases.