Cerebroplacental–Uterine Ratio Improves Prediction of Composite Adverse Perinatal Outcomes in Pregnancies Complicated by Maternal Anemia

OBJECTIVE: To evaluate fetomaternal Doppler changes in pregnancies complicated by maternal anemia and to investigate the predictive value of the cerebroplacental-uterine ratio (CPUR) for composite adverse perinatal outcomes (CAPOs). METHODS: This prospective case-control study included 203 singleton pregnancies at ≥ 28 weeks of gestation. Participants were categorized according to third-trimester hemoglobin levels as moderate anemia (hemoglobin 6-9 g/dL, n = 23), mild anemia (hemoglobin 9-11 g/dL, n = 41), and non-anemic controls (hemoglobin ≥ 11 g/dL, n = 139). Umbilical artery pulsatility index (UA-PI), middle cerebral artery pulsatility index (MCA-PI), and uterine artery pulsatility index (UtA-PI) were measured. The cerebroplacental ratio (CPR) was calculated as MCA-PI/UA-PI, and CPUR was calculated as CPR/mean UtA-PI. CAPO was defined as the presence of at least one of the following: preterm birth, low birth weight, small for gestational age, low fifth-minute Apgar score, abnormal umbilical artery cord blood gas values, or neonatal intensive care unit admission. RESULTS: Women with moderate anemia had significantly lower gestational age at birth, lower birth weight, lower first- and fifth-minute Apgar scores, and worse umbilical artery cord blood gas parameters than controls. The prevalence of small for gestational age neonates, neonatal intensive care unit admission, and CAPO increased progressively with anemia severity. UA-PI and UtA-PI were significantly higher, whereas CPR and CPUR were significantly lower in pregnancies complicated by moderate anemia. Hemoglobin alone showed moderate predictive performance for CAPO prediction (AUC = 0.724, 95% CI: 0.643-0.801, p < 0.001). CPUR demonstrated higher discriminative ability than CPR for predicting CAPO (AUC = 0.841 vs. 0.791, both p < 0.001). In multivariable logistic regression analysis, hemoglobin level, gestational age at birth, UA-PI, UtA-PI, and CPUR remained independent predictors of CAPO. CONCLUSION: Maternal anemia is associated with impaired uteroplacental and fetoplacental hemodynamics and increased adverse perinatal outcomes. CPUR demonstrates superior predictive performance compared with CPR and hemoglobin alone and may serve as a useful adjunctive Doppler marker in the surveillance of pregnancies complicated by maternal anemia.