Effect of fetal presentation on the amniotic fluid index

Abstract

Objective: The aim of this study was to determine whether the amniotic fluid index differs according to whether a fetus is in breech or cephalic presentation. Study Design: Between January 1995 and April 1996 the amniotic fluid index was measured both immediately before and after attempted external cephalic version. Amniotic fluid indexes were measured by a senior obstetric resident or attending physician. Preprocedure amniotic fluid indexes and change in amniotic fluid index after successful and failed external cephalic version were compared with unpaired and paired Student t tests, respectively. P < .05 was considered statistically significant. Results: Thirty consecutive women between 36 and 40 weeks’ gestation with breech presentations were evaluated before undergoing an attempt at external cephalic version. The preprocedure amniotic fluid index was not different ( P = .61) between women who had success (12.1 cm) and failure (11.4 cm) of attempts at external cephalic version. Successful external cephalic version was associated with a statistically significant increase ( P < .0001) in amniotic fluid index with respect to gestations with a persistent breech presentation (3.14 vs –0.35). Conclusion: Successful version from a breech to a cephalic presentation resulted in a significant increase in the amniotic fluid index. This should be considered when a breech presentation with a low normal amniotic fluid index is evaluated. Presentation of the fetus should be considered in evaluating amniotic fluid index distribution curves. (Am J Obstet Gynecol 1999;181:1222-4.)