Fetal cerebroplacental ratio at term gestation in the prediction of adverse perinatal outcome

Abstract

Introdction: Assessment of impedance to blood flow in fetal umbilical artery (UA) and middle cerebral artery (MCA) with Doppler ultrasonography is commonly used in surveillance of fetuses at high risk. Although high UA pulsatility index (PI) and low MCA PI, themselves are predictors of adverse perinatal outcome, combining these two parameters calculating the cerebroplacental ratio (CPR) further improves the predictive value. Objective: To find the association between the cerebroplacental ratio and adverse perinatal outcome. Methods: Prospective cohort study conducted in Teaching Hospital, Anuradhapura. 354 singleton pregnancies at 37-41 weeks gestation were included. Ultrasound scanning performed measuring fetal UAPI and MCAPI and CPR was calculated. Fetuses were followed up for intrapartum adverse outcome categorized as NNU admission, perinatal death, fetal distress, Apgar score < 7 at 5 min and any adverse outcome. Descriptive statistics and the statistical applications for diagnostic test accuracy were used for data analysis. ROC curve were plotted to analyze the predictability of CPR for each category. Results: CPR has a significantly positive ability of predicting any type of adverse event. (AUC=0.501-.623, 95%CI) An overall predictability is shown by the other variables used in the study such as MCAPI (AUC=0.505:95%CI=0.444-0.567) and UAPI 0.518 (95% CI=0.457-0.579). But the predictability of CPR value is more superior to the MCAPI and UAPI values. Identified best cut off value for CPR is 0.8533 for predicting adverse events with 80.3% sensitivity. Conclusion: More reliable predictions to detect adverse perinatal outcomes can be achieved by the CPR value than the UAPI and MCAPI values.