Accuracy of Amniotic Fluid Index and Single Deepest Pocket Measurement in Predicting of Postdate Pregnancy Outcomes

Background: Two techniques for sonographic evaluation of amniotic fluid are Amniotic Fluid Index (AFI) and Single Deepest Pocket (SDP). Objective: To determine the accuracy of Amniotic Fluid Index and Single Deepest Pocket in predicting of postdate pregnancy outcomes. Methods: In this prospective cross-sectional study, 362 pregnant women with gestational age > 40 weeks (postdate pregnancy) were evaluated. Evaluation of amniotic fluid was done for all patients by the measurement of AFI and SDP methods. Pregnancy outcomes and complications including meconiumstained amniotic fluid (MSAF), 5 minutes Apgar score <7, Neonatal Intensive Care Unit (NICU) admission, necessity of cesarean section, and neonatal mortality were evaluated. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and positive likelihood ratio were calculated. Results: Sensitivity and specificity of AFI in diagnosis of MSAF were 68% and 47%, respectively which were higher than SDP. We found higher sensitivity in AFI method than SDP in predicting necessity of cesarean section; 85% vs. 68%, respectively. No association was found between abnormal AFI or SDP and 5 minutes Apgar score <7. Conclusion: AFI is a better method for predicting of MSAF, need for NICU admission, and necessity of cesarean section than SDP in postdate pregnancies.