The Influence of Overweight and Obesity on Maternal Soluble fms-Like Tyrosine Kinase 1 and Its Relationship With Leptin During Pregnancy

We studied obesity-related differences in the relation of maternal levels of leptin to levels of soluble fms-like tyrosine kinase 1 (sFlt1), an antiangiogenic protein that influences placentation and risk of adverse pregnancy outcomes. In a prospective cohort of 286 gravidas, we measured maternal serum levels of sFlt1 and leptin at 5 time points across pregnancy. Analyses stratified on prepregnancy body mass index (< 25 vs >= 25) were done using mixed linear models. The mean leptin concentrations were significantly higher in overweight/obese compared to normal-weight women, while mean sFlt1 levels in second and third trimester were significantly higher in normal weight compared to overweight/obese women. The relationship between sFlt1 and leptin differed between the 2 strata. After controlling for maternal weight, a 1 ng/mL increase in leptin was associated with an 19.4 pg/mL increase in sFlt1 (P = .01) in normal-weight women, while leptin was not associated with sFlt1 (beta = 1.1, P = .75) in overweight/obese women. Such differences suggest that metabolic differences in overweight/obese women compared to their normal weight peers may differentially impact the physiologic changes during pregnancy.