OP16.06: Cerebroplacental ratio and risk of operative delivery for intrapartum fetal compromise at term: does gestational age play a role?

Abstract

Our aims were to evaluate the association between cerebroplacental ratio (CPR) and the need of operative delivery for intrapartum fetal compromise (IFC), and the performance of CPR for predicting operative delivery according to gestational age at delivery. This was a retrospective study of women with singleton pregnancies who were delivered between 37+0 and 41+6 weeks of pregnancy in a single tertiary centre. CPR was recorded within one week of delivery. IFC was defined as the presence of persistent pathological CTG and/or fetal scalp pH < 7.20. The study population was divided into groups according to birth weight (small-for-gestational age (SGA) and appropriate-for-gestational age (AGA)), CPR (< 10th centile and ≥ 10th centile), and gestational age (GA) at delivery (< 40+0 weeks and ≥ 40+0 weeks). A total of 2052 term pregnancies with 18% (n=374) operative deliveries were included. In the group of women who were delivered at < 40+0 weeks (n=839), the proportion of operative deliveries due to IFC was similar both in SGA (CPR < 10th centile 27% vs. CPR ≥ 10th centile 23%; p = 0.617) and AGA (CPR < 10th centile 12% vs. CPR ≥ 10th centile 12%; p = 0.917) groups regardless of CPR. On the other hand, women who delivered at ≥ 40+0 weeks (n=1213) with fetuses with low CPR had a significantly higher proportion of operative deliveries both in SGA (CPR < 10th centile 47% vs. CPR ≥ 10th centile 22%; p = 0.004) and AGA (CPR < 10th centile 31% vs. CPR ≥ 10th centile 19%; p = 0.001) groups. CPR as a predictor for operative delivery showed low sensitivity (< 40+0 weeks 13-33% and ≥ 40+0 weeks 20-39%) for a high false positive rate (< 40+0 weeks 14-29% and ≥ 40+0 weeks 11-17%) irrespective of GA at delivery. In our population, only fetuses with low CPR who were delivered at ≥ 40+0 weeks had a significantly higher risk of operative delivery because of IFC regardless of birth weight. However, CPR performance for predicting operative delivery is low. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.