Oligohydramnios and the appropriately grown fetus

The perinatal implications of oligohydramnios prior to 37 weeks of gestation, in the absence of intrauterine growth restriction (IUGR), rupture of membranes or fetal anomalies, are unknown. We compared the outcomes of 65 women with oligohydramnios (amniotic fluid index ([AFI]less than or equal to 8cm) by sonography to those of a control group matched by sonogram indication. Study patients were between 17 and 37 weeks of gestation, with appropriately grown fetuses on index sonogram and no other detected explanation for amniotic fluid abnormalities. Patients were managed expectantly with fetal testing and follow-up sonograms for fetal growth. Delivery was not recommended solely for oligohydramnios until 37 weeks of gestation. Patients with isolated oligohydramnios prior to 37 weeks of gestation, when compared to a control group with normal amniotic fluid volume, had a significantly higher incidence of premature delivery (odds ratio [OR]3.23, 95% confidence interval [CI]1.4-7.3), but did not appear to be at increased risk of IUGR, intrauterine death, or birth asphyxia.