OBJECTIVE

Gestational diabetes mellitus complicates ∼6% of pregnancies and strongly predicts subsequent type 2 diabetes. It has not been fully elucidated how risk depends on the number of affected pregnancies or how long the excess risk persists.

RESEARCH DESIGN AND METHODS

We assessed reproductive histories in relation to risk of type 2 diabetes using a nationwide cohort of 50,884 women. Among participants who initially did not have diabetes, 3,370 were diagnosed with diabetes during 10 years of follow-up. We used Cox proportional hazards models that allowed risk to depend on age, cumulative number of pregnancies with gestational diabetes mellitus, and time since the most recent affected pregnancy, adjusting for BMI, educational level, and race/ethnicity.