EP17.48: Fetal cerebral blood redistribution in idiopathic polyhydramnios and its impact on perinatal outcomes

The aim of this study was to examine the value of the middle cerebral artery pulsatility index (MCA-PI) in predicting adverse perinatal outcome in pregnancies affected by idiopathic polyhydramnios. This retrospective study included singleton pregnancies with idiopathic polyhydramnios recorded during 2013–2022. Obstetrical and perinatal outcomes were compared between women with MCA-PI<10th percentile and women with MCA-P ≥10th percentile. A composite adverse perinatal outcome was defined as an Apgar score <7 at 5 minutes, umbilical artery pH <7.15, emergent Caesarean delivery(CD) or operative delivery due to fetal distress, neonatal intensive care admission or fetal death Among 45,459 pregnancies, 128 (0.3%) had idiopathic polyhydramnios; 27 exhibited MCA-PI<10th percentile. Among the latter, compared to pregnancies with MCA-PI >10th percentile group, the rates were higher of emergent CD (25.9% vs. 7.9%,p = 0.017) and adverse perinatal outcomes (37.0% vs. 15.8%,p = 0.020). In the MCA-PI <10th percentile group, the median MCA-PI and cerebroplacental ratio were lower: 0.9 vs. 1.7, p < 0.001 and 0.7 vs. 2.1, p < 0.001, respectively. Receiver operating characteristic curve analysis indicated a significant association of MCA-PI with emergent CD/operative delivery for fetal distress (area under curve = 0.672, p = 0.031); the sensitivity was 46.7% and specificity 82.3%. Cerebroplacental ratio values were not associated with adverse perinatal outcomes. Idiopathic polyhydramnios might be associated with fetal cerebral blood flow redistribution, potentially contributing to an increased risk of adverse neonatal outcomes. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.