Antepartum cerebroplacental ratio in low risk pregnancy and its relationship with adverse perinatal outcome: a prospective cohort study

Objectives To assess the relationship of cerebroplacental ratio (CPR) with non-reassuring/abnormal cardiotocography (CTG) tracing and perinatal outcomes like operative delivery, birth weight, NICU admission, meconium-stained liquor, and APGAR score in low-risk pregnancy. Methods This was a prospective cohort study at tertiary center in western India which included low risk singleton pregnancies between 35 and 37+6 weeks with cephalic presentation. Ultrasound was done between 35 and 37+6 weeks gestation including fetal biometry and Doppler for CPR calculation. Patients were divided into two groups, with normal CPR (>10th centile) and abnormal CPR (≤10th centile), and maternal and neonatal outcomes were compared. Results Out of 172 cases enrolled, CPR was abnormal in 55 (31.97 %) patients and normal in 117 (68.02 %) patients. In abnormal CPR group, CTG tracing was reassuring in 61.81 %, non-reassuring in 18.18 %, and abnormal in 20 %. While in normal CPR group, CTG tracing was reassuring in 81.19 %, non-reassuring in 11.11 %, and abnormal in 7.69 %. This was significant difference between the two groups (p=0.027). Cesarean and operative vaginal delivery rates were comparable in both groups, (p value=0.63, 0.33). Lower birth weight was observed in 45.45 % of women in the abnormal CPR group, while 21.36 % of women had low birth weight in the normal CPR group (p value=0.006). No significant difference was found in APGAR score and NICU admissions between the two groups (p-value-0.94, 0.87). Conclusions We conclude that CPR measurement has good negative predictive value for fetal outcome in low risk pregnancy.