Peripartum outcomes of high‐risk pregnancies complicated by oligo‐ and polyhydramnios: A prospective longitudinal study

Abstract

To determine pregnancy outcomes in high-risk non-anomalous singleton pregnancies with oligo- and polyhydramnios. In high-risk pregnancies undergoing antenatal testing, the last amniotic fluid index (AFI) prior to delivery in pregnancies with polyhydramnios (>97.5th percentile) and oligohydramnios (<2.5th percentile) was correlated with pregnancy outcomes. There were 2597 pregnancies with a normal AFI (2.5th-97.5th percentile), 73 with hydramnios (AFI > 97.5th percentile) and 72 with oligohydramnios (<2.5th percentile). Polyhydramnios and oligohydramnios adversely influenced different pregnancy outcomes. Pregnancies with polyhydramnios versus normal AFI were more likely to have: an abnormal tracing influencing delivery (29% vs 17%, odds ratio [OR] = 2.03, 95% confidence interval [CI] 1.19-3.45, P = 0.009), cesarean delivery performed due to fetal labor intolerance (21% vs 7%, OR = 3.89, 95%CI 2.10-7.18, P < 0.001), increased birthweight (P = 0.016), Apgar score <7 at 5 min (8% versus 1%, OR = 6.41, 95%CI 1.12-16.22, P = 0.001) and newborn intensive care unit admission (10% versus 5%, OR = 2.24, 95%CI 1.12-4.49, P = 0.023). Pregnancies with oligohydramnios versus normal AFI had a greater risk of labor induction (18% vs 9%, OR = 3.18, 95%CI 1.62-6.25, P = 0.001), intrauterine growth restriction (25% vs 9%, OR = 3.4, 95%CI 1.94-5.97, P < 0.001) and preterm delivery (29% vs 17%, OR = 1.97, 95%CI 1.17-3.31, P = 0.010). Fetal heart rates influencing delivery, cesarean deliveries for fetal labor intolerance, low 5-min Apgar scores, increased neonatal birthweight, and newborn intensive care unit admissions were more common with polyhydramnios. The fetuses of pregnancies complicated by oligohydramnios had a greater risk of labor induction, intrauterine growth restriction and preterm delivery.