A history of gestational diabetes (GDM) in any pregnancy increases the risk of type 2 diabetes and this risk remains high even after 35 years of their last GDM diagnosis, according to a study reported in Diabetes Care.¹ 

Researchers screened 50,884 women, aged 35 -74 years, from the Sister study to assess the risk of type 2 diabetes. They were telephonically enquired about their reproductive histories in addition to demographic data and medical history including type 2 diabetes. After review of data, 47,471 women were included in the final analysis. They were asked about abnormal glucose tolerance tests or gestational diabetes during each of their pregnancies. Based on their BMI, they were categorized as underweight/normal weight (<25.0 kg/m2), overweight (25.0–29.9 kg/m2) and obese (≥30.0 kg/m2).

The number of women who reported at least one pregnancy with GDM was 1414. These women tended to be younger and also have high BMI. During follow-up over 10 years (mean), there were 3370 incident cases of type 2 diabetes among women who did not have diabetes at baseline. These included 3180 (6.9%) women without a history of GDM and 190 (13.4%) women with GDM.

Women who had had a history of GDM were 2.5 times more likely to develop type 2 diabetes later on in life. Although this risk declined with each decade, it persisted even after 35 years.  The hazard ratios were 3.87 within 6 -15 years after GDM, 3.50 within 16–25 years, 1.95 within 26–35 years, and 1.62 after 35 years. 

Women who had GDM in three or more pregnancies and who were within 6-15 years of their last GDM diagnosis had 7 times higher risk of developing type 2 diabetes than those who did not have GDM. After 35 years, the HR for developing diabetes was 3.08.

Gestational diabetes increases the risk for progression to type 2 diabetes. The risk increases with the number of pregnancies affected and continues to be high over the long-term since the last diagnosis of GDM, as shown in this study. All women with history of gestational diabetes, especially those with multiple affected pregnancies and are overweight/obese, should be regularly screened for type 2 diabetes.

Reference

1. Diaz-Santana MV, et al. Persistence of risk for type 2 diabetes after gestational diabetes mellitus. Diabetes Care. 2022 Apr 1;45(4):864-870. doi: 10.2337/dc21-1430.