Role of umbilicocerebral and cerebroplacental ratios in prediction of perinatal outcome in FGR pregnancies

Aim of our study was to compare the prognostic value of the Umbilical-to-Cerebral ratio (UCR) directly to the Cerebroplacental ratio (CPR) in the prediction of poor perinatal outcomes in pregnancies complicated by Fetal Growth Restriction (FGR). A retrospective study was carried out on pregnant women with either a small-for-gestational age (SGA) fetus or that were diagnosed with FGR. Doppler measurements of the two subgroups were assessed and the correlation between CPR, UCR and relevant outcome parameters was evaluated by performing linear regression analysis, binary logistic analysis and receiver operator characteristic (ROC) curves. Outcomes of interest were mode of delivery, acidosis, preterm delivery, gestational age at birth as well as birthweight and centiles. Boxplots and Scatterplots illustrated the different distribution of CPR and UCR leading to deviant correlational relationships with adverse outcome parameters. In almost all parameters examined, UCR showed a higher independent association with preterm delivery (OR: 5.85, CI 2.23–15.34), APGAR score < 7 (OR: 3.52; CI 1.58–7.85) as well as weight under 10th centile (OR: 2.04; CI 0.97–4.28) in binary logistic regression compared to CPR which was only associated with preterm delivery (OR: 0.38; CI 0.22–0.66) and APGAR score < 7 (OR: 0.27; CI 0.06–1.13). When combined with different ultrasound parameters in order to differentiate between SGA and FGR during pregnancy, odds ratios for UCR were highly significant compared to odds ratios for CPR (OR: 0.065, 0.168–0.901; p = 0.027; OR: 0.810, 0.369–1.781; p = 0.601). ROC curves plotted for CPR and UCR showed almost identical moderate prediction performance. Since UCR is a better discriminator of Doppler values in abnormal range it presents a viable option to Doppler parameters and ratios that are used in clinical practice. UCR and CPR showed equal prognostic accuracy conserning sensitivity and specificity for adverse perinatal outcome, while adding UA PI and GA_scan increased prognostic accuracy regarding negative outcomes.