Prelabor screening at term using the cerebroplacental ratio and placental growth factor: a pragmatic randomized open label Phase 2 trial

Abstract

BACKGROUND AND OBJECTIVE:In some women placental function may not be adequate to meet fetal growth requirements in late pregnancy or the additional demands during labor thus predisposing these infants to intrapartum fetal compromise (IFC) and subsequent serious morbidity and mortality. The objective of this study was to determine if the introduction of a pre-labor screening test at term combining the cerebroplacental ratio and maternal placental growth factor level would result in a reduction in a composite of adverse outcomes. STUDY DESIGN:Single-site, non-blinded, randomized controlled trial conducted at a tertiary hospital in Brisbane, Australia. Eligible women were randomized to either receive the screening test performed between 37-38 weeks or routine obstetric care. Screen positive women were offered induction of labor. The primary outcome was a composite of: emergency cesarean for non-reassuring fetal status (fetal distress) or severe neonatal acidosis or low Apgar score or stillbirth or neonatal death. RESULTS:Women were recruited and randomized (n=501) between April 2017 to January 2019. 63/249 (25·3%) of the screened group compared to 56/252 (22·2%) of the control group experienced the primary outcome (Relative Risk (RR) = 1·14 [95% CI 0·83 - 1·56]; p = 0·418). Women who screened positive were more likely to require operative delivery for fetal distress, have meconium stained liquor, pathological FHR abnormalities and have infants with lower birth weight compared to women that screened negative. CONCLUSION:The introduction of this test did not result in improvements in intrapartum intervention rates or neonatal outcomes. However, it did show discriminatory potential and future research should focus on refining the thresholds used.