Role of the cerebroplacental ratio and non-stress test in predicting adverse perinatal outcomes in high-risk pregnancies.

OBJECTIVE

High-risk pregnancies are associated with increased risk of fetal and maternal morbidity and mortality. The non-stress test (NST) is the standard method for antenatal fetal monitoring, while the cerebroplacental ratio (CPR) has emerged as a noninvasive tool for predicting adverse perinatal outcomes. We aimed to evaluate the role of the CPR and NST in predicting adverse perinatal outcomes in high-risk pregnancies.

METHODS

A prospective study was conducted with 672 high-risk pregnant women at Haiphong Hospital of Obstetrics and Gynecology in Vietnam from February 2024 to February 2025. All participants had a gestational age of 32 weeks or more. The CPR and an NST were performed on each woman. They were monitored until delivery to identify adverse perinatal outcomes, including cesarean section due to fetal distress, a 5-minute Apgar score below 7, admission to the neonatal intensive care unit, and perinatal death.

RESULTS

There was a significant difference between CPR and NST between groups with adverse and normal perinatal outcomes (p < 0.05). After adjusting for confounding factors, significant associations were found between CPR and adverse perinatal outcomes in women with hypertensive disorders of pregnancy, fetal growth restriction, and hyperglycemia in pregnancy, with OR (95% CI) of 5.92 (1.38-25.45), 11.11 (1.61-76.76), and 6.66 (1.53-28.99), respectively. Similarly, NST results showed significant associations, with ORs (95% CI) of 13.56 (2.59-71.05), 15.44 (2.46-96.98), and 15.35 (3.01-78.33), respectively. While the sensitivity of CPR and NST in high-risk cases is low, their specificity exceeds 90%, and their overall accuracy exceeds 80%. The positive likelihood ratio (LR+) of the NST exceeds that of the CPR in predicting adverse perinatal outcomes across different high-risk groups. Notably, the LR+ for the combined CPR and NST in women with high-risk pregnancies, hypertensive disorders of pregnancy, fetal growth restriction, and hyperglycemia in pregnancy was 5.14, 16.2, 32.14, and 42.4, respectively.

CONCLUSION

In addition to NST, CPR is a valuable predictor of adverse perinatal outcomes in high-risk pregnancies. The NST shows greater predictive accuracy than the CPR when forecasting adverse perinatal outcomes across different high-risk groups. Combining these two indices provides a stronger prediction for adverse perinatal outcomes.