Meconium-Stained Amniotic Fluid and Neonatal Morbidity in Low-Risk Pregnancies at Term: The Effect of Gestational Age.

To assess the association of gestational age at delivery with perinatal outcome in low-risk term deliveries complicated by meconium-stained amniotic fluid (MSAF).  We retrospectively analyzed all singleton deliveries that underwent a trial of labor in a single hospital (2007-2013). Exclusion criteria included pregnancy-related complications (e.g., hypertensive disorders, diabetes, oligohydramnios, and fetal anomalies). First, only deliveries with MSAF were analyzed. Perinatal outcome of deliveries at 37 to 38 weeks (early term) and 41 to 41 weeks (late term) were compared with those at 39 to 40 weeks of gestation (full term). Additionally, a gestational age based comparison was made between the risk for neonatal respiratory morbidity in deliveries with clear amniotic fluid and MSAF.  During the study period, 28,248 deliveries were considered as low risk. Of them, 3,399 (12.0%) were diagnosed with MSAF and were divided to full term ( = 2,413), early term ( = 405), and late term ( = 581). In multivariate analysis, MSAF at early term was associated with neonatal jaundice, need for phototherapy, and neonatal sepsis. In a gestational age based stratification, when comparing between deliveries with clear amniotic fluid and those with MSAF, late term had the highest odds (4.2 vs. 0.5%;  < 0.001) for neonatal respiratory morbidity.  Gestational age was associated with specific complications in deliveries complicated by MSAF and otherwise low-risk deliveries.