Clinical Usefulness of the Soluble Fms-Like Kinase-1/Placental Growth Factor Ratio in Obstetric Management

Soluble fms-like tyrosine kinase-1 (sFlt-1) is a circulating antiangiogenic protein for which the level increases during the last 2 months of normal pregnancy. In contrast, placental growth factor (PlGF), an angiogenic protein, has a decreased level during the same period. These changes in angiogenic-associated protein levels during pregnancy occur earlier and are more pronounced in women who subsequently develop preeclampsia. Based on these findings, the sFlt-1/PlGF ratio has been introduced into the field of obstetrics over the past several years as a predictive tool for the prediction of placental insufficiency, including preeclampsia and/or fetal growth restriction. Since 2017, this test has been available in Korea and can be performed after 24 weeks of gestation in pregnant women at a high risk for placental insufficiency. Importantly, this marker not only predicts the development of preeclampsia but it is also associated with the severity and progression of diseases, and adverse pregnancy outcomes. In addition, as this test reflects placental function, it is expected to be useful for predicting the onset of labor and the success of labor induction. Accordingly, its clinical utility in the management of obstetric complications has emerged and it continues to expand. In this article, the aim was to summarize the clinical usefulness of the sFlt-1/PIGF ratio by reviewing the literature.