Prognostic Value of Cerebroplacental Ratio in Appropriate-for-Gestational-Age Fetuses Before Induction of Labor in Late-Term Pregnancies.

Purpose:  To evaluate the relationship between cerebroplacental ratio (CPR) and the need for operative delivery due to intrapartum fetal compromise (IFC) and adverse perinatal outcome (APO) in appropriate-for-gestational-age (AGA) late-term pregnancies undergoing induction of labor. The predictive performance of CPR was also assessed.

Materials And Methods:  Retrospective study including singleton AGA pregnancies that underwent elective induction of labor between 41 + 0 and 41 + 6 weeks and were delivered before 42 + 0 weeks. IFC was defined as persistent pathological CTG or pathological CTG and fetal scalp pH < 7.20. Operative delivery included instrumental vaginal delivery (IVD) and cesarean section (CS). APO was defined as a composite of umbilical artery pH < 7.20, Apgar score < 7 at 5 minutes, and admission to the neonatal intensive care unit for > 24 hours.

Results:  The study included 314 women with 32 (10 %) IVDs and 49 (16 %) CSs due to IFC and 85 (27 %) APO cases. Fetuses with CPR < 10 percentile showed a significantly higher rate of operative delivery for IFC (40 % (21/52) vs. 23 % (60/262); p = 0.008) yet not a significantly higher rate of APO (31 % (16/52) vs. 26 % (69/262); p = 0.511). The predictive values of CPR for operative delivery due to IFC and APO showed sensitivities of 26 % and 19 %, specificities of 87 % and 84 %, positive LRs of 2.0 and 1.2, and negative LRs of 0.85 and 0.96, respectively.

Conclusion:  Low CPR in AGA late-term pregnancies undergoing elective induction of labor was associated with a higher risk of operative delivery for IFC without increasing the APO rate. However, the predictive value of CPR was poor.