Temporal Changes in Fetal and Maternal Parameters in Early-Onset Fetal Growth Restriction: A Multicenter, Retrospective Cohort Study

Objective(s): Timing of birth is complex in early-onset fetal growth restriction (FGR) and the literature is limited regarding the exact sequence of changes in antenatal parameters. This study aimed to examine this sequence in a large early-onset FGR cohort. Design: Multicenter, retrospective cohort study. Setting: Six tertiary care hospitals in the Netherlands. Population: A post hoc analysis of the OPtimal TIming of antenatal COrticosteroids in early-onset fetal growth REstriction (OPTICORE) study was performed. Methods: Repeated measures of antenatal parameters were assessed routinely from diagnosis to birth. Mixed-effects models were used to determine the probability of abnormality (binary) and the trend (Z-score, continuous) over time for each parameter (< 32 and ≥ 32 weeks). Main Outcome Measures: The time sequence of changes in fetal and maternal health parameters from diagnosis to birth in early-onset FGR pregnancies. Results: A total of 1453 patients were included, of whom 1025 patients gave birth < 32 weeks and 428 ≥ 32 weeks, with median gestational ages of 29 + 3 weeks (IQR 27 + 6, 30 + 5) and 34 + 4 weeks (IQR 33 + 0, 37 + 0), respectively. The most apparent changes in fetal parameters in the last days preceding birth comprised: absent/reversed end-diastolic velocity of the umbilical artery and cardiotocography abnormalities. Regarding maternal parameters, an increased probability of antihypertensive agent(s) use was seen shortly preceding birth < 32 weeks. Conclusion(s): This large cohort of early-onset FGR pregnancies provides a time sequence of fetal and maternal health parameters from diagnosis to birth, which could inform clinical management.