Association of Middle Cerebral Artery Doppler Parameters With Neonatal Outcomes in Idiopathic Polyhydramnios: A Prospective Case–Control Study

OBJECTIVE: To compare middle cerebral artery (MCA) Doppler parameters in patients diagnosed with idiopathic polyhydramnios and those with a normal amniotic fluid index (AFI) and to investigate the effects of MCA Doppler findings on neonatal outcomes. MATERIALS AND METHODS: This study was designed as a prospective case-control study and conducted at a single tertiary care center. A total of 166 patients, including 83 with idiopathic polyhydramnios and 83 healthy controls between 24 and 35 weeks of gestation were included. We divided the patients diagnosed with polyhydramnios into three groups as mild, moderate, and severe. MCA Doppler evaluations were performed for each patient. RESULTS: MCA Doppler parameters pulsatility index (PI) and resistive index (RI) were significantly lower in pregnancies with idiopathic polyhydramnios (p < 0.05). A significant difference was observed in neonatal intensive care unit (NICU) admissions between the two groups (p < 0.05). Receiver operating characteristic analysis showed that the optimal cut-off value of the MCA PI for predicting NICU admissions was 1.37, with a sensitivity of 69% and a specificity of 50% (area under the curve = 0.759; p = 0.021). There was no difference in UA-PI and CPR levels between both groups (p > 0.05). Univariable regression analysis showed that polyhydramnios was associated with a 7.48-fold increase in the odds of NICU admission. The MCA PI level, gestational age at birth, and first minute Apgar score were lower in the severe polyhydramnios group compared to the mild polyhydramnios group. CONCLUSION: MCA PI and RI values were found to be lower in fetuses with idiopathic polyhydramnios compared to those with a normal AFI, suggesting altered fetal cerebral vascular resistance that may be compatible with blood-flow redistribution. MCA Doppler parameters showed an exploratory association with NICU admission and may provide additional information for neonatal risk assessment; they do not prove fetal hypoxia.