Obstetric outcomes of isolated oligohydramnios during early-term, full-term and late-term periods and determination of optimal timing of delivery.

Abstract

Our aim was to evaluate the obstetric outcomes of isolated oligohydramnios during the early-term, full-term, and late-term periods, and to determine the optimal timing of delivery. A retrospective study was performed at a tertiary center. Isolated oligohydramnios cases were divided into early-term, full-term, and late-term groups. Evaluated outcomes were fetal birthweight, 5-min Apgar score<7, meconium-stained amniotic fluid, neonatal intensive care unit admission, transient tachypnea of newborn (TTN), requirement of ventilator, newborn jaundice, mode of delivery, induction of labor, and undiagnosed small-for-gestational-age fetus before delivery. Composite outcome was defined as perinatal outcomes taken together (neonatal intensive care unit admission, TTN, requirement of ventilator, and newborn jaundice). The study period included 1213 cases of term isolated oligohydramnios. Within this cohort there were 347 early-term, 781 full-term and 85 late-term patients. The cesarean rate and the rate of newborn jaundice were higher in early-term cases (37.8% and 3.5%, respectively) than in full-term cases (30.1% and 0.9%, respectively). Meconium-stained amniotic fluid was higher in late-term than full-term cases. Timing of delivery did not affect occurrence of TTN, 5-min Apgar score<7, ventilator requirement, or composite outcome. In total, 15-17% of isolated oligohydramnios cases involved undetected small-for-gestational-age fetuses. As this study was not a randomized controlled trial, a decisive conclusion may not be possible. However, until well-designed controlled studies are conducted, expectant management may be appropriate up to the full-term period and induction of labor may be appropriate management when the full-term period is reached.