OP05.01: Impact of Doppler and gestational age on the prediction of adverse perinatal outcome in fetuses with late‐onset fetal growth restriction

To determine the value of gestational age (GA) and Doppler in late-onset fetal growth restriction (lateFGR) for prediction of adverse perinatal outcome (APO). Observational study on a cohort of lateFGR diagnosed at the Hospital Clínico Universidad de Chile between 2006 and 2019. The outcome was APO: a composite including ≥1 of the following: emergency Caesarean section, stillbirth, early neonatal death, perinatal asphyxia, admission to NICU and use of mechanical ventilation. Univariate and multivariate logistic regression identified variables associated with APO. A decision tree was constructed using CHAID. 495 cases of lateFGR were included. The APO rate was 20.4%. Predictors of APO were: cerebroplacental ratio (CPR) <p5: OR = 1.6 (0.99–2.59), p = 0.05, and GA < 34 weeks at FGR diagnosis: OR = 2.0 (1.22–3.26), p = 0.006. A decision tree was developed. GA significantly influenced APO probability: >34 weeks, the APO rate was 17.2%, while between 32–34 weeks, it was 29.1% (p = 0.003). The determination of CPR became crucial in the GA group between 32 and 34 weeks. When CPR was >p5, the APO rate was 25%, whereas < p5, it was 39.5% (p = 0.1) This study demonstrates that APO in late-onset FGR fetuses is directly related to altered CPR and gestational age at diagnosis. The use of CPR appears to have a predictive role in the late-onset FGR subgroup between 32 and 34 weeks of gestation.