Amniotic Fluid Index in Term Pregnancy: A Poor Predictor of Perinatal Outcome

Abstract

Objective: To determine the predictive value of Antepartum Amniotic Fluid Index in term pregnancy for perinatal outcome including fetal distress, mode of delivery, and infant Apgar score.

Study Design: Observational as well as comparative study.

Place and Duration of Study: This study was carried out in Unit-III at Sir Ganga Ram Hospital, Lahore from 14-05-2002 to 15-06-2003.

Patients and Methods: During this study 500 patients with singleton pregnancy were selected and Amniotic Fluid Index (AFI) was evaluated within 4 days of delivery in these patients with technique of Phelan et al. All outcome variables of these pregnancies were recorded on printed proformas. On the bases of AFI measurements patients were divided in two groups. Those who have AFI > 50mm and < 50 mm. The significance of difference or comparison of means was measured by Chais-quare test (by Yats corrections) and Probability values were calculated. Perinatal outcomes in pregnancies with amniotic fluid index of ≤ 50mm were compared with those with an amniotic fluid index of > 50 mm. Finally AFI was evaluated as a predictor of neonatal outcome by calculating % positive and negative predictive values of AFI for the selected outcomes.

Results: According to results AFI showed significant positive predictive values for poor infants Apgar scores. For the chances of operative delivery it showed NPV 73.118% but only 36.72% PPV. There were more likely poor predictive values of AFI for the other selected outcomes.

Conclusion: Instead of the AFI, alternative technique of ultrasonographically assessing amniotic fluid may be used in clinical practice.

Key Words:  Amniotic fluid index, AFI.