Plasma leptin influences gestational weight gain and postpartum weight retention

Background: Leptin, a product of the obese (ob) gene, is released from adipocytes. At the same body mass index, women have higher concentrations than men. Thus, during pregnancy, leptin may influence gestational weight gain and retention of a portion of that gain postpartum. Objective: We examined the relation between plasma leptin at entry to prenatal care and subsequent changes in weight from entry to prenatal care (at 17 wk gestation, baseline) until 6 mo postpartum. Design: This was an observational study of leptin, gestational weight gain, and postpartum weight retention (at 6 wk and 6 mo postpartum) in 103 low-income pregnant women from Camden, NJ, with a pregravid body mass index (in kg/m²) in the normal range (19.8-26). Results: After potential confounding variables were controlled for, leptin at entry significantly (P < 0.05) predicted weight gain in pregnancy, including measured rate of weight gain (̄ ± SEE: 0.25 ± 0.13 kg·unit log leptin^{- 1}·wk^-1), measured rate of third-trimester weight gain (0.37 ± 0.15 kg·unit log leptin^-1·wk^-1), rate of weight gain from recalled pregravid weight (0.23 ± 0.09 kg·unit log leptin^-1 wk^-1), and net rate of gestational weight gain (0.22 ± 0.09 kg·unit log leptin^-1·wk^-1). The leptin concentration at entry also significantly predicted retained weight in the postpartum period (at 6 mo: 7.29 ± 3.33 kg/unit log leptin at entry) and marginally predicted changes in the sum of skinfold thicknesses (at 6 mo: 14.7 ± 7.5 mm/unit log leptin at entry). Conclusion: These results suggest that a high leptin concentration at entry to prenatal care may predict an increased risk of over-weight and obesity in vulnerable women.