Cerebroplacental Ratio Versus Umbilicocerebral Ratio in Predicting Adverse Neonatal Outcomes: A Prospective Observational Study

Antenatal identification of “at risk” fetuses is crucial for timely intervention to aid in achieving better perinatal outcomes. One such means is the use of Doppler for fetal hemodynamic monitoring. Using the same our study aimed to compare the utility of two Doppler parameters, Cerebroplacental ratio (CPR) and Umbilicocerebral ratio (UCR), in predicting adverse neonatal outcomes.

A total of 280 antenatal women participated in a prospective observational study following 28 weeks of gestation, and CPR and UCR (inverse of CPR) were determined by serial Doppler ultrasound. This was converted to gestational age-specific percentiles and Z-scores using Fetal Medicine Foundation (FMF) as a reference for CPR and study by Acharya et al. for UCR.

Out of the 277 participants analyzed, abnormal Doppler parameters were present in 27 (9.7%) women. The abnormal Doppler group had a considerably greater occurrence of adverse outcomes, including Apgar score < 7 at 1 min, small for dates, neonatal hypoglycemia, requirement of ventilatory support, prolonged hospitalization, NICU (Neonatal intensive care unit) admission, and a composite of adverse outcomes. ROC (Receiver operating characteristic) curves exhibited an AUC (Area Under the Curve) of 0.76 for both CPR and UCR and a slightly higher AUC of 0.83 and 0.85 for their centiles and Z-scores, respectively.

Both CPR and UCR Doppler parameters are no different from each other in predicting adverse neonatal outcomes. The same holds true even on conversion to gestational age-specific centiles and Z-scores.