Borderline or Marginal Amniotic Fluid Index and Peripartum Outcomes: a Review of the Literature

The predictive accuracy of a borderline amniotic fluid index (AFI) for an adverse pregnancy outcome is uncertain. Pregnancy outcomes of a borderline versus normal AFI suggest an increased risk of meconium-stained fluid, intrauterine growth restriction, cesarean delivery for a nonreassuring fetal heart rate, low Apgar scores, and neonatal intensive care unit admission with borderline fluid. These results are inconclusive because of study design variations, the absence of receiver-operating characteristic curves, our inability to calculate likelihood ratios, and a lack of randomized trials. There is currently insufficient evidence to recommend additional antenatal testing delivery based on a borderline AFI. Sonography could be considered for evaluating fetal growth until a definitive association or lack of an association between a borderline AFI and intrauterine growth restriction/small size for gestational age can be determined.