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

ABSTRACT

AIM: 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. METHODS: 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). RESULTS: 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. CONCLUSION: 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.