sFlt-1 to PlGF ratio cut-offs to predict adverse pregnancy outcomes in early-onset FGR and SGA: a prospective observational study

This is a prospective, observational study, conducted in a tertiary referral hospital. We enrolled 175 singleton pregnancies with estimated foetal weight below the 10th centile between 20 + 0 and 31 + 6 weeks. Placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and fetoplacental circulation were assessed at the time of diagnosis. Receiver operating characteristic curves were used to assess the performance of sFlt-1/PlGF for predicting adverse perinatal outcomes (APO). The optimal cut-offs to predict each adverse outcome were calculated and the resulting areas under the curve (AUC) were compared to those calculated from the cut-off points of 38, 85 and 110. The need for delivery at <30 and <34 weeks and APO were the main outcome measures. The optimal cut-off points to predict APO, delivery <30 and <34 weeks were 24.9, 116.7 and 97.5, respectively. None of them proved to be superior to 38, 85 or 110 for predicting any adverse pregnancy outcome. Impact StatementWhat is already known on this subject? Soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are biomarkers of placental dysfunction. High sFlt-1/PlGF values predict adverse perinatal outcomes in preeclampsia (PE).Whatdothe results of this study add? No specific thresholds have been described to identify early-onset foetal growth restriction (FGR) and small for gestational age (SGA) foetuses at higher risk of adverse outcomes. This study describes these specific cut-offs and compares their predictive capacity to those described for PE.What are the implications of these findings for clinical practice and/or further research? The sFlt-1/PlGF cut-off points of 38, 85 and 110 might be useful for ruling out the occurrence of APO and the need for elective delivery at <30 and at <34 weeks from the moment of diagnosis in early-onset FGR and SGA. These cut-offs could aid Doppler studies in the distinction between FGR and SGA.