To compare the diagnostic performance of Amniotic Fluid Index (AFI) and Single Deep Pocket (SDP) in detecting Oligohydramnios, and to evaluate their association with perinatal outcomes in term singleton pregnancies

AFI vs SDP in Oligohydramnios

Abstract

BACKGROUND & OBJECTIVE:  Term oligohydramnios is linked with fetal distress, cesarean delivery and neonatal complications. Amniotic Fluid Index (AFI) and Single Deepest Pocket (SDP) are the most commonly used ultrasound techniques to measure amniotic fluid volume, but their diagnostic accuracy is unclear. To compare the sensitivity and specificity of AFI and SDP for the diagnosis of Oligohydramnios, and to assess the relationship between AFI, SDP and perinatal outcomes in term singleton pregnancies.

METHODOLOGY: This comparative cross-sectional study was conducted at the Department of Radiology, PINUM Hospital, Faisalabad, over 9 months. A total of 100 women with singleton, low-risk pregnancies at ≥37 weeks were included. Amniotic fluid volume was measured during the same ultrasound session using AFI and SDP. AFI ≤5 cm and SDP <2 cm were considered Oligohydramnios. Maternal and neonatal outcomes were recorded. Data were analyzed using an independent t-test and Chi-square test; p≤0.05 was considered significant.

RESULTS: SDP detected more oligohydramnios cases (24%) than AFI (13%). SDP-defined Oligohydramnios was significantly associated with higher caesarean rates (66.7% vs 31%; p=0.009) and neonatal incubation (62.5% vs 33.8%; p=0.030). NICU admissions were higher but not statistically significant. Birth weight and Apgar scores were lower in oligohydramnios cases.

CONCLUSION: SDP shows a stronger association with adverse perinatal outcomes than AFI and may be preferred for amniotic fluid assessment in term pregnancies.