Long-Term Risk of Type 2 Diabetes After Preterm Delivery or Hypertensive Disorders of Pregnancy

To examine long-term diabetes risk after preterm delivery or hypertensive disorders of pregnancy in a large population-based cohort. This retrospective cohort study included all women with a singleton delivery in Sweden during 1973-2015 and no preexisting diabetes mellitus. Participants were followed up for development of type 2 diabetes identified from nationwide outpatient and inpatient diagnoses through 2018. Cox regression was used to compute hazard ratios (HRs) for the association between preterm delivery or hypertensive disorders of pregnancy and type 2 diabetes with adjustment for gestational diabetes and other maternal factors. Co-sibling analyses assessed for confounding by shared familial (genetic or environmental) factors. Overall, 2,184,417 women were included. Within 10 years after delivery, adjusted HRs for type 2 diabetes associated with specific pregnancy outcomes were as follows: any preterm delivery (before 37 weeks of gestation), 1.96 (95% CI, 1.83-2.09); extremely preterm delivery (22-27 weeks), 2.53 (95% CI, 2.03-3.16); and hypertensive disorders of pregnancy, 1.52 (95% CI, 1.43-1.63). All HRs remained significantly elevated (1.1-1.7-fold) 30-46 years after delivery. These findings were largely unexplained by shared familial factors. In this large national cohort, preterm delivery and hypertensive disorders of pregnancy were associated with increased risk for type 2 diabetes up to 46 years later. Women with these pregnancy complications are candidates for early preventive actions and long-term monitoring for type 2 diabetes.