OBJECTIVE: This study examined the long-term consequences for offspring born to mothers with pregestational type 1 diabetes regarding mortality, hospital admissions, and medication. We also examined the association between HbA1c levels during pregnancy and mortality and incidence of hospital admissions.

RESEARCH DESIGN AND METHODS: We performed a prospective combined clinical and register-based cohort study comparing mortality, hospital admissions, and use of medication in offspring (n = 1,326) of women with pregestational type 1 diabetes (index children) with matched control subjects (n = 131,884). We also examined the association between HbA1c levels during pregnancy and mortality and the incidence of hospital admissions. Participants were monitored from birth to the age of 13-21 years.

RESULTS: Overall mortality was significantly increased for index children (hazard ratio 2.10, 95% CI 1.33-3.30, P = 0.001). The incidence of hospital admissions for index children was significantly increased (incidence rate ratio [IRR] 1.45, 95% CI 1.38-1.53, P < 0.001), and this was the case for all age groups until the age of 15 years. The incidence of hospital admissions among index children was positively associated with maternal HbA1c before pregnancy and in the first trimester. In addition, the overall use of medication was increased in index children (IRR 1.13, 95% CI 1.07-1.19, P < 0.001).

CONCLUSIONS: Type 1 diabetes during pregnancy has long-term implications on the health of offspring, with increased mortality, incidence of hospital admissions, and use of medication. Among mothers with type 1 diabetes, glycemic regulation is positively associated with incidence of hospital admissions in offspring.