UCLA

OBJECTIVE: To examine the association between age at menarche and risk of gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: A prospective cohort study of 42,109 eligible pregnancies from 27,482 women in the Nurses' Health Study II. RESULTS: The adjusted risk ratios for GDM across the age at menarche categories (≤11, 12, 13, and ≥14 years) were 1.34 (95% CI 1.14-1.58), 1.13 (0.97-1.31), 1.11 (0.95-1.29), and 1.00 (referent; P for trend = 0.0005), respectively. Analysis of the mediating effect indicated that 42.1% (P = 0.0007) of the association was mediated through prepregnancy BMI. CONCLUSIONS: These findings suggested that earlier menarche was significantly associated with an increased risk of GDM. This association was largely mediated through prepregnancy excessive body adiposity.