GDM in ≥ 1 pregnancy is associated with a significant risk of developing type 2 DM in the affected women. The risk remains elevated for > 35 years, according to a recent study.
Gestational diabetes mellitus (GDM) is characterized by the onset of hyperglycemia in the second or third trimester in pregnant women without a previous non-GDM diagnosis. This condition is associated with pancreatic beta-cell dysfunction in the background of insulin resistance. GDM may progress and lead to an increased risk for type 2 diabetes mellitus (DM) following pregnancy. Despite the association between GDM and the subsequent development of type 2 DM, the underlying risks and mechanisms are not fully known. A nationwide cohort study, published in the journal Diabetes Care, assessed the relationship between reproductive history and type 2 DM.
A total of 50,844 women were included in this cohort. The authors employed the Cox proportional hazards model as it allowed for the risk to depend on duration since the recent pregnancy with GDM, age, and a cumulative number of GDM-related pregnancies adjusted for race, ethnicity, body mass index (BMI), and educational level.
Among the study participants, 1414 women reported a minimum of one pregnancy with GDM at the baseline. These women had a higher baseline BMI and were relatively younger. At the follow-up period, 3180 women without GDM history and 190 women with GDM history reported developing type 2 DM. The age-specific risk for developing type 2 DM was elevated in women with a history of ≥ 1 pregnancy with GDM, 6-15 years following an affected pregnancy. The risk of developing type 2 DM increased steeply in multiple affected pregnancies. Age-specific associations between type 2 DM and GDM attenuate with time after pregnancy with GDM. The study recorded an estimated reduction of 24% in the hazard ratio per decade. The risk, however, remains elevated for > 35 years.
In summary, the onset of GDM predicted markedly increased rates of development of type 2 DM, with the relative risk increasing with each additional pregnancy with GDM. Despite a reduction in the estimated hazard ratio with increasing time following an affected pregnancy, the risk remains elevated for > 35 years. The study implies that women with a GDM history should undergo regular screening for type 2 DM.
Diaz-Santana, M. V., O’Brien, K. M., Park, Y. M., Sandler, D. P., & Weinberg, C. R. (2022). Persistence of Risk for Type 2 Diabetes After Gestational Diabetes Mellitus. Diabetes Care, 45(4), 864-870. https://doi.org/10.2337/dc21-1430