The association between a history of gestational diabetes mellitus and future risk for female malignancies

Objective: To investigate whether patients with a history of gestational diabetes mellitus (GDM) have an increased future risk for female malignancies. Study design: A population-based study compared the incidence of long-term female malignancies (ovary, uterine, breast, and uterine cervix) in a cohort of women with and without a diagnosis of GDM. Deliveries occurred between the years 1988–2013, with a mean follow-up duration of 12 years. Women with known malignancies prior to the index pregnancy were excluded. Kaplan–Meier survival curve was used to estimate cumulative incidence of malignancies. Cox proportional hazards models were used to estimate the adjusted hazard ratios (HR) for female malignancy. Results: During the study period, 1,04,715 deliveries met the inclusion criteria; 9.4% (n = 9893) occurred in patients with a history of GDM in at least one of their pregnancies. During the follow-up period, patients with GDM had a significantly increased risk of being diagnosed with female malignancies, including ovarian, uterine, and breast cancer. Using a Kaplan–Meier survival curve, patients with a previous diagnosis of GDM had a significantly higher cumulative incidence of female malignancies. Using a Cox proportional hazards model, adjusted for confounders, such as parity, maternal age, and fertility treatments, a history of GDM remained independently associated with female malignancies (adjusted HR, 1.3; 95% CI 1.2–1.6; P = 0.001). Conclusion: Patients with a history of GDM have an increased risk for future breast, ovarian, and uterine malignancies.