Increased risk of hypertension after gestational diabetes mellitus: findings from a large prospective cohort study.

OBJECTIVE: Whether a history of gestational diabetes mellitus (GDM) is associated with an increased risk of hypertension after the index pregnancy is not well established.

RESEARCH DESIGN AND METHODS: We investigated the association between GDM and subsequent risk of hypertension after the index pregnancy among 25,305 women who reported at least one singleton pregnancy between 1991 and 2007 in the Nurses' Health Study II.

RESULTS: During 16 years of follow-up, GDM developed in 1,414 women (5.6%) and hypertension developed in 3,138. A multivariable Cox proportional hazards model showed women with a history of GDM had a 26% increased risk of developing hypertension compared with those without a history of GDM (hazard ratio 1.26 [95% CI 1.11-1.43]; P=0.0004). These results were independent of pregnancy hypertension or subsequent type 2 diabetes.

CONCLUSIONS: These results indicate that women with GDM are at a significant increased risk of developing hypertension after the index pregnancy.