Third-trimester cerebroplacental ratio as a predictor of neonatal outcome in a low-risk pregnancy

Abstract

Objective: To study the role of the cerebroplacental ratio (CPR) in the prediction of adverse neonatal outcomes and mode of delivery in low-risk women at 37–41 weeks’ gestation. Materials and methods: Three hundred and seventy low-risk women with singleton pregnancy at 37–41 weeks of gestation, with known last menstrual period (LMP), were prospectively evaluated over a period of 1 year in a medical college setting. Doppler examination was performed and the indices recorded. Defined maternal and neonatal outcomes were studied. Nonparametric tests such as test for comparison of population means, test for comparison of proportions, and tests of diagnostic accuracy were performed. Receiver operating characteristic (ROC) curves were used to determine the area under the curve. Results: Total 78 subjects had CPR below 5th centile. The mean CPR value at the 5th centile was 1.2. The mean (SD) of CPR for the total population was 1.48 (+​0.39); the mean (SD) value for CPR was lowest for the infants requiring neonatal intensive care unit (NICU) admission (1.12 ± 0.22). The CPR below the 5th centile had an independent association with APGAR < 7 at 5 minutes, induced labor, and NICU admission. Birth weight centile did not affect this association. Conclusion: The CPR below the 5th centile was associated with a higher risk of obstetric intervention for intrapartum fetal compromise and adverse perinatal outcomes in subjects with low-risk pregnancy at term.