Predicting intrapartum fetal compromise using the fetal cerebro-umbilical ratio

Abstract

IntroductionThe aim of this study was to explore the association between the cerebro-umbilical ratio measured at 35–37 weeks and intrapartum fetal compromise. MethodsThis retrospective cross sectional study was conducted at the Mater Mothers' Hospital in Brisbane, Australia. Maternal demographics and fetal Doppler indices at 35–37 weeks gestation for 1381 women were correlated with intrapartum and neonatal outcomes. ResultsBabies born by caesarean section or instrumental delivery for fetal compromise had the lowest median cerebro-umbilical ratio 1.60 (IQR 1.22–2.08) compared to all other delivery groups (vaginal delivery, emergency delivery for failure to progress, emergency caesarean section for other reasons or elective caesarean section). The percentage of infants with a cerebro-umbilical ratio <10th centile that required emergency delivery (caesarean section or instrumental delivery) for fetal compromise was 22%, whereas only 7.3% of infants with a cerebro-umbilical ratio between the 10th–90th centile and 9.6% of infants with a cerebro-umbilical ratio > 90th centile required delivery for the same indication (p < 0.001). A lower cerebro-umbilical ratio was associated with an increased risk of emergency delivery for fetal compromise, OR 2.03 (95% CI 1.41–2.92), p < 0.0001. DiscussionThis study suggests that a low fetal cerebro-umbilical ratio measured at 35–37 weeks is associated with a greater risk of intrapartum compromise. This is a relatively simple technique which could be used to risk stratify women in diverse healthcare settings.