sFlt-1/PlGF ratio for the prediction of the time of delivery

Purpose: The soluble fms-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) ratio has been shown to be a useful parameter for the diagnosis and prediction of preeclampsia (PE). An increased sFlt-1/PlGF ratio can be closely linked to the need to deliver. The aim of the study was to examine the mean time until delivery (MTUD) in pregnant women with a strongly increased sFlt-1/PlGF ratio. Methods: From 2010 to 2018, the sFlt-1/PlGF ratio was determined in 995 singleton pregnancies with diagnosis or suspicion of PE/HELLP syndrome and/or intrauterine growth restriction (IUGR). MTUD of patients with a value above 655 in < 34 weeks of gestation (group 1: n = 13) and above 201 in ≥ 34 weeks of gestation (group 2: n = 15) was calculated. Patients with a value > 85 but < 655 in < 34 weeks of gestation (group 3: n = 70) and a value > 110 but < 201 (group 4: n = 44) in ≥ 34 weeks of gestation acted as controls. Results: 28 pregnant women with severely elevated sFlt-1/PlGF ratio and 114 controls were included. In group 1, MTUD was longer compared to group 2 without reaching statistical significance (96.7 h ± 132.2 vs. 47.7 h ± 44, p = 0.222). In pregnancies < 34 weeks of gestation (early onset), MTUD was significantly longer in group 3 compared to group 1 (361 h ± 317.3 vs. 96.7 h ± 132.2, p < 0.001). In pregnancies ≥ 34 weeks of gestation (late onset), MTUD was significantly longer in group 4 compared to group 2 (123.6 h ± 139.2 vs. 47.7 h ± 44, p = 0.002). Conclusions: The sFlt-1/PlGF ratio is suitable for decision-making regarding close monitoring of high-risk patients and need for lung maturation. However, for planning of delivery itself further prospective interventional studies are required to define its role as outcome predictor.