Polyhydramnios is an independent risk factor for perinatal mortality and intrapartum morbidity in preterm delivery

To investigate the clinical significance of polyhydramnios as a predictor of perinatal death and intrapartum morbidity in patients with preterm delivery.

The study population consisted of 4211 patients with singleton gestation, intact membranes and preterm delivery (< 37 weeks). Two groups were identified and compared according to the sonographic assessment of the amniotic fluid volume: increased and normal amniotic fluid. Analyses were conducted for the entire cohort as well as for the cohort excluding from each group all cases with congenital malformations. Logistic regression was used to assess the unique contribution of polyhydramnios to mortality and morbidity in the presence of other known risk factors.

The prevalence of polyhydramnios among women who delivered preterm was 5% (210/4211) including and 3.7% (142/3818) excluding the cases of congenital malformations, respectively. Polyhydramnios was associated with a higher rate of diabetes, large for gestational age neonates, fetal malpresentation at delivery, previous perinatal death and with a lower Apgar score at 1 and 5 min. Polyhydramnios was an independent predictor of perinatal mortality and intrapartum morbidity. When adjusted for well recognized risk factors for perinatal mortality and intrapartum morbidity (e.g. diabetes, severe pregnancy induced hypertension, multiparity, congenital malformation, previous perinatal death, low gestational age at delivery), the presence of polyhydramnios significantly increased the rate of perinatal mortality (odds ratio (OR) 5.8; 95% confidence interval (CI) 3.68-9.11) and of intrapartum morbidity (OR 2.8; 95% CI 1.94-4.03).

In the setting of preterm delivery, polyhydramnios is an independent risk factor for perinatal mortality and intrapartum complications even in the absence of congenital malformation and other conditions traditionally associated with increased perinatal mortality and morbidity.