First-Trimester Soluble fms-like Tyrosine Kinase 1 (sFlt-1) for the Prediction of Preterm Preeclampsia.

While soluble fms-like tyrosine kinase 1 (sFlt-1) is used to predict preeclampsia (PE) and its severity in late pregnancy, we aimed to clarify its role in early pregnancy. Using prospective cohorts, we estimated the association between sFlt-1, adjusted for gestational age, and preterm PE. sFlt-1 was significantly decreased in the first trimester, mostly before the 13th week, and significantly increased in the third trimester in those who developed preterm PE and particularly early-onset PE. We hypothesize that sFlt-1 evolves from low to high values in early to late pregnancy among women with preterm and early-onset PE.