Effect of Meconium-Stained Amniotic Fluid on Perinatal Complications in Low-Risk Pregnancies at Term

Abstract

Objective: This study aims to determine the impact of meconium-stained amniotic fluid (MSAF) in low-risk pregnancies at term on pregnancy outcome.

Study design: A retrospective cohort study of women with MSAF during labor who delivered in a tertiary hospital at 37 to 41(+6) weeks of gestation (2007-2013). Exclusion criteria included: multiple gestations, noncephalic presentation, fetal structural/chromosomal anomalies, hypertensive disorders, diabetes, oligohydramnios, or small for gestational age. Pregnancy outcome of women with MSAF (N = 4,893) was compared with a control group of women without MSAF (N = 39,651). Neonatal respiratory morbidity was defined as the presence of any of the following: respiratory distress syndrome, transient tachypnea of the newborn, meconium aspiration syndrome, or need for ventilatory support.

Results: Overall, 10.9% of low-risk pregnancies at term were diagnosed with MSAF. Compared with the controls, women with MSAF had higher rates of nulliparity, gestational age at delivery ≥ 41 weeks, induction of labor, nonreassuring fetal heart rate, and operative deliveries. In multivariate analysis MSAF was associated with operative delivery (odds ratio [OR], 1.82; 95% confidence interval [CI], 1.63-2.09; p < 0.001), cesarean section (OR, 1.48; 95% CI, 1.31-1.69; p < 0.001), respiratory morbidity (OR, 4.74; 95% CI, 3.87-5.82; p < 0.001), and increased risk for short-term neonatal morbidity.

Conclusions: MSAF is associated with a higher rate of adverse perinatal outcome even in low-risk pregnancies at term.