Outcomes in oligohydramnios: the role of etiology in predicting pulmonary morbidity/mortality.

Objective Early-onset oligohydramnios is typically secondary to renal-urinary anomalies (RUA) or preterm premature rupture of membranes (PPROM). We compared neonatal pulmonary outcomes between these etiologies. Methods We conducted a retrospective cohort study of women with oligohydramnios identified before 24 completed weeks of gestation attributed to either PPROM or RUA. Patients were excluded if other fetal anomalies were noted. Respiratory morbidity was assessed by the need for oxygen at 36 corrected weeks or at hospital discharge. Results Of 116 eligible patients, 54 chose elective pregnancy termination. A total of 39.5% of PPROM (n=17/43) and 36.8% of RUA (n=7/19) pregnancies experienced pre-viable loss (P=1.00). Significantly fewer PPROM live births resulted in neonatal mortality (26.9% vs. 75.0%, P<0.01). There was no difference in respiratory morbidity (57.9% vs. 66.6%, P=1.00). The collective incidence of respiratory mortality and morbidity was not different between etiologies (P=0.06). Conclusion This analysis suggests that the prognoses for oligohydramnios due to pre-viable PPROM vs. renal anomalies are similarly grave, though RUA infants experienced a higher rate of neonatal respiratory mortality.