Relationship of Maternal Weight Status Before, During, and After Pregnancy with Breast Milk Hormone Concentrations

Objective The aim of this study was to test associations of prepregnancy BMI, gestational weight gain, oral glucose challenge test results, and postpartum weight loss as predictors of breast milk leptin, insulin, and adiponectin concentrations and whether these relationships vary over time. Methods Milk was collected at 1 and 3 months from 135 exclusively breastfeeding women from the longitudinal Mothers and Infants Linked for Healthy Growth (MILk) study. Hormones were assayed in skimmed samples using ELISA. Mixed‐effects linear regression models were employed to assess main effects and effect‐by‐time interactions on hormone concentrations. Results In adjusted models, BMI was positively associated with milk leptin (P