Familial aggregation of type 2 diabetes and chronic hypertension in women with gestational diabetes mellitus.

Objective: To perform a case-control study to assess the extent to which women with a positive parental history of type 2 diabetes and/or chronic hypertension experienced an increased risk of developing gestational diabetes mellitus (GDM).
Study Design: Participants (133 GDM cases and 373 controls) provided information on first-degree family history of the 2 conditions and other covariates of interest in interviews. Logistic regression procedures were used to derive odds ratios and 95% confidence intervals adjusted for confounding by maternal age, race/ethnicity and prepregnancy adiposity.
Results: As compared with women with no parental history of diabetes, women with a maternal-only (odds ratio = 2.0), paternal-only (odds ratio = 2.3) or both maternal and paternal history of diabetes (odds ratio = 3.8) experienced a statistically significant increased risk of GDM. The odds ratio for women with a positive parental history of diabetes and hypertension was 2.6 (95% confidence interval, 1.3-5.3). Women with a diabetic sibling had an 8.4-fold increased risk of GDM (95% confidence interval, 2.1-33.4). First-degree family history of chronic hypertension was predictive of GDM risk but only when hypertension was associated with a diagnosis of diabetes.
Conclusion: Our results are consistent with the thesis that family history of diabetes (alone or when associated with hypertension) reflects genetic and behavioral factors whereby women may be predisposed to an increased GDM risk.