The correlation between the cerebroplacental ratio and fetal arterial blood gas in appropriate-for-gestational-age fetuses: A cross-sectional study

Background: The cerebroplacental ratio (CPR) is an important index for predicting adverse pregnancy outcomes in small-for-gestational-age and appropriate-for gestational-age fetuses. Objective: To find out whether there is an association between the CPR level and the blood cord gases analysis in appropriate for gestational age fetuses. Materials and Methods: This cross-sectional study included 347 pregnant women at the gestational age of 37-40 wk. Patients had an appropriate-for-gestational-age fetus confirmed from their first ultrasonography results. Participants were divided into two groups based on their CPR, measured before delivery. Finally, after delivery, arterial blood gas level and the incidence of emergency cesarean section, intrapartum fetal distress and neonatal intensive care unit admissions were compared between the two groups. Results: Fifty-four (15.6%) cases had a CPR below the detection limit of the assay. The incidence of fetal distress, emergency cesarean section, neonatal hospitalization in the neonatal intensive care unit, and pH 7.2 were significantly lower in women with CPR ≥ 0.67 multiples than in women with a CPR 0.67 multiples of the median. Conclusion: The third-trimester CPR is an independent predictor of stillbirth and perinatal mortality and morbidity. The role of UA/MCA Doppler and the CPR in assessing the risk of adverse pregnancy outcomes should be evaluated prospectively.