Multiple pregnancies and the risk of diabetes mellitus in postmenopausal women.

OBJECTIVE: We aimed to investigate whether the number of pregnancies during childbearing age was associated with diabetes in postmenopausal women with no history of gestational diabetes.

METHODS: Our data source was the continuous National Health and Nutrition Examination Survey 1999 to 2014. We selected 9,138 postmenopausal women over 40 years old who did not have a history of gestational diabetes during pregnancy. Logistic regression analyses were applied for the association of the number of pregnancies with diabetes.

RESULTS: We found women with ≥4 pregnancies had significantly greater fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), 2-hour plasma glucose, and the Homeostatic Model Assessment of Insulin Resistance than those with two to three pregnancies (all P < 0.01). These women also had a significantly higher prevalence of diabetes (28.4% vs 20.7%; P < 0.001). Using the two to three pregnancies group as the reference, we observed a positive association of log-FPG and log-HbA1c with 4 or more pregnancies after adjustment for sociodemographic, lifestyle, and reproductive factors, and body mass index (both P < 0.05). Compared to women with two to three pregnancies, the odds ratios for diabetes were 1.31 (95% confidence interval [CI] 1.01-1.71) for women who never got pregnant and 1.28 (95% CI 1.10-1.48) for those with at least 4 pregnancies after multivariate adjustment.

CONCLUSIONS: At least 4 pregnancies through childbearing age may be a potential risk factor for diabetes in postmenopausal women without a history of gestational diabetes.