334: Comparing cerebro-placental (CPR) and umbilico-cerebral (UCR) Doppler ratios for the prediction of adverse neonatal outcomes

Abstract

The CPR (Middle cerebral artery PI/ Umbilical artery PI) has been shown to improve identification of pregnancies complicated by fetal growth restriction at risk for adverse neonatal outcomes. However, recent studies suggest that the inverted ratio, umbilico-cerebral ratio (UCR), may be a better index to predict these outcomes. We aimed to compare CPR to UCR Doppler in the prediction of short term adverse neonatal outcomes in pregnancies affected by fetal growth restriction. We conducted a secondary analysis using data from a prospective study on women referred for fetal growth ultrasounds between 26 and 36 weeks of gestation and with an EFW < 20th percentile by Hadlock standard. Umbilical artery and middle cerebral artery Doppler assessments were performed. Our primary outcome was a composite of adverse outcomes, including any of the following: umbilical cord arterial pH < 7.10, APGARS at 5 minutes < 7, NICU admission, respiratory distress syndrome (RDS), seizure, grade III or IV IVH or death. The CPR and UCR were converted into Z-scores adjusted for gestational age at ultrasound. We calculated sensitivity and specificity of the two Doppler parameters. Logistic regression analysis was performed, ROC curves plotted and the area under the ROC curve (AUC) were compared between CPR and UCR. Of 197 women meeting inclusion criteria, 27 (13.7%) had a composite adverse neonatal outcome. The median Z-scores for CPR and UCR were - 0.082 and -0.16, respectively. The sensitivity and specificity were similar, however, the positive predictive value (PPV) was higher for CPR and the negative predictive values (NPV) were similar. The AUC for CPR and UCR were 0.65 and 0.64, respectively. The CPR and UCR Z-scores performed poorly as predictors of adverse neonatal outcomes when compared with published data on using absolute CPR ratio. Our findings do not support the use of UCR Z-scores to evaluate fetuses with growth restriction.View Large Image Figure ViewerDownload Hi-res image Download (PPT)