Labor Induction in Women with Isolated Polyhydramnios at Term: A Multicenter Retrospective Cohort Analysis

Background: With the increasing popularity of elective induction after 39 + 0 weeks, the question of whether induction of labor (IOL) is safe in women with isolated polyhydramnios has become more relevant. We aimed to evaluate the pregnancy outcomes associated with IOL among women with and without isolated polyhydramnios. Methods: This was a multicenter retrospective cohort that included women who underwent induction of labor at term. The study compared women who underwent IOL due to isolated polyhydramnios to low-risk women who underwent elective IOL due to gestational age only. The main outcome measure was a composite adverse maternal outcome, while the secondary outcomes included maternal and neonatal adverse pregnancy outcomes. Results: During the study period, 1004 women underwent IOL at term and met inclusion and exclusion criteria; 162 had isolated polyhydramnios, and 842 had a normal amount of amniotic fluid. Women who had isolated polyhydramnios had higher rates of the composite adverse maternal outcome (28.7% vs. 20.4%, p = 0.02), prolonged hospital stay, perineal tear grade 3/4, postpartum hemorrhage, and neonatal hypoglycemia. Multivariate analyses revealed that among women with IOL, polyhydramnios was significantly associated with adverse composite maternal outcome [aOR 1.98 (1.27-3.10), p < 0.01]. Conclusions: IOL in women with isolated polyhydramnios at term was associated with worse perinatal outcomes compared to low-risk women who underwent elective IOL. Our findings suggest that the management of women with polyhydramnios cannot be extrapolated from studies of low-risk populations and that clinical decision-making should take into account the individual patient's risk factors and preferences.