Idiopathic polyhydramnios and pregnancy outcome: systematic review and meta-analysis

Objective: To analyze outcomes of singleton pregnancies with idiopathic polyhydramnios through a systematic review and meta-analysis.

Methods: Electronic databases, including MEDLINE, OVID, EBSCO, Cochrane collection and Science Citation Index, were searched from 1946 to 2019. Gray literature and tables of contents of relevant journals were also screened. Prospective and retrospective studies with a control group were included. Two authors independently reviewed the abstracts retrieved from the literature search. Inclusion criteria were: studies documented in English, singleton pregnancy and idiopathic polyhydramnios determined by amniotic fluid volume assessment on ultrasound. Exclusion criteria were: maternal diabetes, fetal structural or chromosomal anomaly, alloimmunization and intrauterine fetal infection.

Results: Twelve studies met the inclusion criteria, giving a total of 2392 patients with idiopathic polyhydramnios and 160 135 patients with normal amniotic fluid volume. Pregnancies complicated by idiopathic polyhydramnios were at a higher risk of neonatal death (odds ratio (OR), 8.68 (95% CI, 2.91-25.87)), intrauterine fetal demise (OR, 7.64 (95% CI, 2.50-23.38)), neonatal intensive care unit admission (OR, 1.94 (95% CI, 1.45-2.59)), 5-min Apgar score < 7 (OR, 2.21 (95% CI, 1.34-3.62)), macrosomia (OR, 2.93 (95% CI, 2.39-3.59)), malpresentation (OR, 2.73 (95% CI, 2.06-3.61)) and Cesarean delivery (OR, 2.31 (95% CI, 1.79-2.99)).

Conclusions: This study suggests that pregnancies complicated by idiopathic polyhydramnios are at increased risk of adverse outcome. Future investigations should aim to determine an amniotic fluid volume threshold above which antenatal fetal surveillance is appropriate in the management of these pregnancies. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.