Cerebroplacental ratio and middle cerebral artery doppler indices as associations with maternal and neonatal outcomes in term pregnancies undergoing labor induction or augmentation: A cross-sectional study

ABSTRACT Background Placental insufficiency remains a leading cause of adverse perinatal outcomes. The cerebroplacental ratio (CPR) has emerged as a hemodynamic marker reflecting fetal adaptive responses to hypoxia. Its predictive value in term pregnancies requiring obstetric intervention to achieve delivery (labor induction or augmentation) requires further characterization. Objectives Building on this background, our goal was to evaluate the association between middle cerebral artery (MCA) Doppler parameters and CPR with maternal and neonatal outcomes in term pregnant women undergoing labor induction or augmentation. Methods This cross-sectional study enrolled 314 singleton term pregnancies (≥37 weeks) admitted for labor induction or augmentation at Kosar Hospital, Urmia, Iran (April 2022–January 2023). Participants underwent pre-induction Doppler ultrasonography. We assessed MCA pulsatility index (PI), umbilical artery (UA) PI, and CPR (MCA-PI/UA-PI). Primary outcomes included mode of delivery, 5-minute Apgar score, umbilical cord arterial pH, and neonatal intensive care unit (NICU) admission. We employed Chi-square tests, multivariable logistic regression, and receiver operating characteristic (ROC) curve analysis. Results Mean maternal age was 30.01±7.42 years with gestational age of 39.29±1.02 weeks. Cesarean delivery occurred in 116 cases (36.9%). Abnormal CPR (<1.08) was identified in 51 participants (16.2%). Abnormal CPR was significantly associated with higher cesarean rates (72.5% vs. 30.0%; adjusted odds ratio [OR]=6.12, 95% confidence interval [CI]: 3.18–11.78), increased NICU admission (9.8% vs. 1.1%; P=0.001), and reduced cord arterial pH (7.17±0.06 vs. 7.20±0.05; P=0.007 ). However, sensitivity analysis restricted to objective cesarean indications (failure to progress and failed induction) showed attenuation of this association (OR=4.56; 95% CI: 2.34–8.89), suggesting the primary cesarean association may be partially influenced by clinician knowledge of CPR status. CPR demonstrated moderate discriminative ability compared to individual Doppler indices (area under the curve for cesarean delivery: 0.71; 95% CI: 0.64–0.78). Conclusions Low CPR in term pregnancies undergoing labor induction or augmentation shows a significant association with adverse perinatal outcomes. However, the association with cesarean delivery should be interpreted cautiously given the lack of clinician blinding, which may have substantially inflated this relationship. CPR demonstrates moderate discriminative ability for objective neonatal outcomes (cord pH, NICU admission), which are less susceptible to observer bias. The moderate area under the curve (0.71-0.78) and low sensitivity (32-63%) indicate that CPR has limited value as a standalone screening test, and many fetuses destined for adverse outcomes will have normal CPR values. CPR should not be used to guide clinical decision-making in isolation. Well-designed prospective trials with clinician blinding are essential to establish whether CPR-guided management improves perinatal outcomes and to quantify the true predictive value of this marker independent of observer bias.