Associations Between Maternal Obesity and Pregnancy Hyperglycemia and Timing of Puberty Onset in Adolescent Girls: A Population-Based Study

Ai Kubo, Julianna Deardorff, Cecile A Laurent, Assiamira Ferrara, Louise C Greenspan, Charles P Quesenberry, Lawrence H Kushi

Early puberty is associated with adverse health outcomes. We investigated whether in utero exposure to maternal obesity is associated with daughters' pubertal timing using 15,267 racially/ethnically diverse Kaiser Permanente Northern California members age 6-11 years with pediatrician-assessed Tanner staging (2003-2017). We extracted maternal body mass index (BMI) during pregnancy from the electronic health record. Using a proportional hazards model with interval censoring we examined the associations between maternal obesity and girl's pubertal timing, and effect modification by race/ethnicity and mediation by pre-pubertal BMI. Maternal obesity (BMI ≥30 kg/m2) or overweight (BMI 25-29.9 kg/m2) was associated with earlier breast onset in girls [hazard ratio (HR) = 1.39, 95% confidence interval (CI): 1.30, 1.49; HR = 1.21, 95% CI: 1.13, 1.29, respectively], adjusting for girls' race/ethnicity, maternal age, education, parity and smoking during pregnancy. There was interaction by race/ethnicity for associations between maternal obesity and girls' pubic hair onset: associations were strongest among Asian and white girls [HR = 1.53, 95% CI: 1.24, 1.90; HR = 1.34, 95% CI: 1.18, 1.52, respectively] and absent for African-American girls. Adjustment for girls' pre-pubertal BMI only slightly attenuated associations. Our results suggest the importance of maternal metabolic factors during pregnancy on girls' pubertal timing and potential differences in the associations by race/ethnicity.