RESUMO
INTRODUCTION: There are two methods to diagnose oligohydramnios: maximal vertical pocket (MVP) and amniotic fluid index (AFI). Following a recent large Cochrane review and other studies, MVP is being recommended as the method of choice by professional societies, after it was shown to result in fewer inductions of labor and C-sections (CS), without compromising neonatal outcome. There is controversy regarding the management of isolated oligohydramnios (IO). It is unclear whether this finding reflects an underlying pathological process, and therefore management protocols differ between different institutions. Studies have shown a higher rate of CS (RR of >2) in IO. Whether this is a true complication of IO or is a result of different confounders like labor inductions and primigravidity is unclear. The effects on neonatal outcomes are also unclear; whereas some authors did not show any adverse effects, others have shown higher rates of neonatal intensive care unit (NICU) admissions, lower Apgar scores and higher rate of Meconium aspiration syndrome. Some studies have shown a higher rate of undiagnosed small for gestational age (SGA) in IO pregnancies. There is no consensus regarding the optimal management and time of delivery. Until now, common practice was to induce labor at term, and some advocate induction in late preterm. Recently, the growing awareness to early term morbidity has led practitioners to question the benefit of early induction. There are several studies that have shown maternal hydration to improve AFI, but there is insufficient data to show the effect on outcomes. In conclusion, many questions regarding IO are still unanswered, and further research, specifically RCT studies, is needed.