Factors associated with prospective leptin concentrations throughout pregnancy in pregestational normal weight, overweight and obese women.

ABSTRACT

BACKGROUND: Leptin concentrations increase throughout pregnancy but little is known about factors that influence this physiological change and whether they differ according to pregestational body mass index (BMI). OBJECTIVE: To assess whether longitudinal trends of leptin in pregnancy are influenced by biochemical, anthropometric and lifestyle factors in women with normal weight (NW), overweight (OW) or obese (OB) pregestational BMI. DESIGN AND METHODS: Prospective cohort of 232 pregnant women followed at 5-13th, 20-26th and 30-36th gestational weeks. The effect of selected variables on longitudinal behaviour of plasma leptin concentrations, stratifying for NW (18·5-24·9 kg/m(2) ), OW (25-29·9 kg/m(2) ) and OB (≥30·0 kg/m(2) ) pregestational BMI was assessed through longitudinal linear mixed-effects models. RESULTS: The multiple regression model for women with NW revealed associations of maternal body weight (ß = 0·714, CI = 0·491 to 0·937), serum HDL-cholesterol (ß = 0·239, CI =0·089 to 0·388) and C-reactive protein (CRP) (ß = -0·138, CI = -0·272 to -0·004) with plasma leptin concentrations. Maternal body weight (ß = -0·871, CI = 0·475 to 1·267) and serum HDL-cholesterol concentrations (ß = 0·315, CI = -0·022 to 0·651) were also associated with leptin in OW women. In OB women, serum HDL-cholesterol (ß = 0·722, CI = 0·219 to 1·226), maternal body weight (ß = 0·666, CI = 0·187 to 1·145), triglycerides concentrations (ß = -0·130, CI = -0·241 to -0·020) and dietary carbohydrate (ß = 0·075, CI = 0·023 to 0·126) were significantly associated with plasma leptin. CONCLUSION: Maternal body weight and serum concentrations of HDL-cholesterol were associated with leptin changes independent of pregestational BMI. Serum CRP concentrations were associated with leptin only in NW women and serum triglycerides concentrations and dietary carbohydrate only in OB. These results indicate that factors that influence leptin concentrations differ according to pregestational BMI.