Abstract Context Gestational diabetes mellitus (GDM) is the most common medical complication of pregnancy and associated with type 2 diabetes, which is associated with breast cancer and kidney cancer. However, little is known about the risk of cancer following a GDM diagnosis. Objective This study aimed to test the hypothesis that a history of GDM associates with increased risk of breast, gynecological, thyroid and kidney cancer. Methods National cohort study, based on Danish registry data. The study population included a group of women exposed to GDM in their pregnancy leading to delivery between 2000-2019 or 1978-1997, and a 1:10 matched non-exposed group, matched on calendar period of delivery, the woman´s age (birth year) and the woman´s registered region of residence at delivery. Poisson regression adjusting for educational level was conducted. Results Of the 314,742 deliveries included, 28,613 deliveries were in the exposed group, 286,129 in the non-exposed. The median follow-up time was 8.1 years. We found no increased risk of the selected cancers combined (adjusted incidence rate ratio (aIRR) 1.05 (95% CI, 0.94-1.18)), breast cancer (aIRR 1.02 (95% CI, 0.89-1.17)), gynecological cancer (aIRR 1.00 (95% CI, 0.79-1.26)), or thyroid cancer (aIRR 1.26 (95% CI, 0.86-1.82)). However, an increased risk of kidney cancer was seen in women with previous GDM compared with women without GDM (aIRR 1.92 (95% CI, 1.10-3.33)), although a very small absolute risk. Conclusions No elevated risk was found for the selected cancers combined. Women with previous GDM had an increased risk of kidney cancer, a rare cancer form.
Madsen et al. (2026) studied this question.