Transient Isolated Polyhydramnios and Perinatal Outcomes

Purpose To evaluate labor and perinatal outcomes of transient isolated polyhydramnios. Materials and Methods A retrospective cohort study (2008-2013) at a university-affiliated, tertiary medical center. Eligibility was limited to patients with singleton gestations, no maternal diabetes or known structural/chromosomal anomalies, and no rupture of the membranes prior to delivery, at > 34 weeks of gestation. All women underwent routine sonogram for estimation of fetal weight (sEFW) between 28-34 weeks of gestation, and a second routine sonogram at admission. We compared women diagnosed with polyhydramnios at the time of the sEFW which later resolved, with women who had normal AFI during the sEFW. Results Overall, 44 263 women delivered during this time period, of which 292 (0.7 %) with transient polyhydramnios (study group) and 29 682 with a normal amniotic fluid level (control group) were eligible for analysis. Women with transient polyhydramnios had a higher risk for assisted vaginal delivery (AVD), mainly due to abnormal/intermediate fetal heart rate tracings (aOR 2.3, 95 % CI 1.2-5.5), and a higher risk for cesarean delivery (CD), mostly because of labor dystocia (aOR 2.5, 95 % CI 1.2-5.1 for 1st stage arrest and aOR 3.4, 95 % CI 1.6-7.2) for 2nd stage arrest), suspected macrosomia (aOR 3.2, 95 % CI 1.6-6.6) and malpresentation (aOR 6.6, 95 % CI 2.0-21.1). Conclusion Transient isolated polyhydramnios detected during the sonogram at 28-32 weeks of gestation is an independent risk factor for the need for obstetrical intervention during labor.