Maternal pre-pregnancy BMI, gestational weight gain, and age at menarche in daughters.

Life course theory suggests that early life experiences can shape health over a lifetime and across generations. Associations between maternal pregnancy experience and daughters' age at menarche are not well understood. We examined whether maternal pre-pregnancy BMI and gestational weight gain (GWG) were independently related to daughters' age at menarche. Consistent with a life course perspective, we also examined whether maternal GWG, birth weight, and prepubertal BMI mediated the relationship between pre-pregnancy BMI and daughter's menarcheal age. We examined 2,497 mother-daughter pairs from the 1979 National Longitudinal Survey of Youth. Survival analysis with Cox proportional hazards was used to estimate whether maternal pre-pregnancy overweight/obesity (BMI ≥ 25.0 kg/m(2)) and GWG adequacy (inadequate, recommended, and excessive) were associated with risk for earlier menarche among girls, controlling for important covariates. Analyses were conducted to examine the mediating roles of GWG adequacy, child birth weight and prepubertal BMI. Adjusting for covariates, pre-pregnancy overweight/obesity (HR = 1.20, 95 % CI 1.06, 1.36) and excess GWG (HR = 1.13, 95 % CI 1.01, 1.27) were associated with daughters' earlier menarche, while inadequate GWG was not. The association between maternal pre-pregnancy weight and daughters' menarcheal timing was not mediated by daughter's birth weight, prepubertal BMI or maternal GWG. Maternal factors, before and during pregnancy, are potentially important determinants of daughters' menarcheal timing and are amenable to intervention. Further research is needed to better understand pathways through which these factors operate.