Outcomes of fetal lower urinary tract obstruction based on timing of oligohydramnios onset

ObjectiveFetal Lower Urinary Tract Obstruction (LUTO) is associated with oligohydramnios and significant fetal morbidity, resulting in poor lung development and perinatal death. However, oligohydramnios may develop at different gestational periods, and the impact of timing on fetal outcomes remains unknown. Our objective was to characterize the impact onset of oligohydramnios had on prenatal outcomes.MethodsThis study is a retrospective cohort study of all patients with a prenatal diagnosis of LUTO at our tertiary referral center from 2014 to 2023. All patients underwent detailed ultrasonography and interdisciplinary counseling and were subsequently delivered at our institution. Data were obtained from electronic medical records and complete extraction was required for final inclusion.ResultsDuring the study time period, 93 patients met inclusion criteria of which 68 (73.1%) developed oligohydramnios during their pregnancy. 63 (93%) of these pregnancies resulted in livebirths with 28 (41.1%) perinatal deaths. Onset of oligohydramnios was earlier in pregnancies with perinatal death (23 vs. 28 weeks, p = 0.004) and associated with pulmonary hypoplasia.ConclusionsOur data show the impact of oligohydramnios timing in pregnancy on pulmonary hyperplasia and ultimately perinatal death. This allows for detailed patient counseling on the impact oligohydramnios may have on pregnancies by the gestational age of onset. What is already known about this topic?Fetal Lower Urinary Tract Obstruction may result in oligohydramnios, which results in increased perinatal morbidity and mortality.What does this study add?The gestational age onset of oligohydramnios prior to the completion of critical lung development results in pulmonary hypoplasia and increased perinatal mortality.