Increased serum levels of sFlt-1/PlGF ratio in preeclamptic women with onset at

Abstract

Our first aim was to construct gestational-age-specific reference ranges of serum levels of soluble fms-like tyrosine kinase 1 (sFlt-1), placental growth factor (PlGF), and the sFlt-1/PlGF ratio at 19-38 weeks of gestation. Our second aim was to compare the serum levels of sFlt-1, PlGF, and the sFlt-1/PlGF ratio in 81 women with PE which occurred at <32, 32-33, 34-35, and ≥36 weeks. Serum levels of sFlt-1 and PlGF were measured by automated immunoassays (Elecsys sFlt-1 and Elecsys PlGF). We constructed the normal reference ranges of log10sFlt-1, log10PlGF, and the log10(sFlt-1/PlGF) between 19 and 38 weeks using 309 samples, which could be represented by a quadratic curve. The cut-off levels were defined as the 5th and 95th percentiles of their gestational-age-specific reference ranges. The frequencies of high sFlt-1, low PlGF, and a high sFlt-1/PlGF ratio in women with an onset at <32 weeks were all 100%, whereas there were no groups showing 100% abnormalities of sFlt-1, PlGF or the sFlt-1/PlGF ratio in women with an onset at 32-33, 34-35, and ≥36 weeks. The levels of sFlt-1, PlGF, and the sFlt-1/PlGF ratio in women with an onset at <32 weeks were significantly different from those in women with an onset at ≥32-33 weeks, although the levels of sFlt-1, PlGF, and the sFlt-1/PlGF ratio in women with an onset at 32-33, 34-35, and ≥36 weeks were almost the same. The appropriate threshold weeks for defining early-onset PE might be 32+0 weeks rather than 34+0 or 36+0 weeks.