Cerebroplacental Ratio Superior to Fetal Weight for Assessing Intrapartum Compromise, finds study
A recent study found that the cerebroplacental ratio (CPR) found by Doppler ultrasound, is a better predictor of intrapartum fetal compromise (IFC) and adverse perinatal outcomes (APO) than fetal weight measurements alone as per the details published in the journal European Journal of Obstetrics & Gynecology and Reproductive Biology.
During pregnancy, fetal well-being surveillance at term helps rule out any nutritional dysfunction affecting fetal neurogenesis. Ultrasound, the gold standard test, has the drawback of traditionally identifying fetuses below the 10th percentile. Not all small fetuses suffer from nutritional compromise as sometimes large fetuses too can suffer from complications like intrapartum fetal compromise. Hence precise tools are necessary to identify cases of fetal compromise as fetal size alone does not work.
Hence, researchers proposed a new hemodynamic model that uses cerebroplacental ratio (CPR) based on middle cerebral and umbilical artery Doppler to improve fetal health risks in the near term. Contrary to the traditional method of using fetal weight this method identifies fetuses with normal weight but abnormal CPR. CPR works to identify the altered blood pattern as despite normal weight late-onset growth restriction can trigger cerebral vasodilation which can lower the impedence in the vessels. This is detected by the CPR which can explain the adverse outcomes seen in certain fetuses that are appropriate for gestational age.
Effectiveness:
- CPR emerged as a winner in predicting the APO and IFC when estimated fetal weight (EFW) was compared with the multiples of the median (MoM) of CPR.
- Based on the abnormal or normal CPR and EFW, cases were categorized into 4 groups by plotting CPR MoM against EFW centiles which showed that CPR MoM was strongly associated with IFC and APO than abnormal weight alone.
- CPR MoM consistently outperformed EFW centile in predicting IFC using univariable logistic regression.
- Even multivariable regression analysis showed that CPR MoM is the consistently significant predictor of adverse outcomes, including stillbirth, APO, and IFC close to delivery.
- Prediction accuracy improved with the examination dates getting close to labor as within 2 weeks of labor CPR MoM, labor induction, and parity were important but within a day of labor, CPR MoM and induction of labor became key predictors.
- 3D and contour graphs also showed that changes in CPR were more significant than fetal weight alterations in predicting the outcomes.
Thus, the researchers concluded that CPR is more important and reliable in predicting adverse outcomes and assessing fetal well-being than fetal weight near term.
Further reading: Morales-Roselló J, Khalil A. Prediction of intrapartum fetal compromise at the end of pregnancy; is Doppler, and not weight, that matters. Eur J Obstet Gynecol Reprod Biol. 2024;301:102-104. doi:10.1016/j.ejogrb.2024.07.070
