Association between Preexisting Type 1 and Type 2 Diabetes and Severe Maternal Morbidity

Comorbidities complicate pregnancy and increase the likelihood of severe maternal morbidity (SMM) but less is known about the distinct risk of SMM associated with type 1 and type 2 pregestational diabetes across the pregnancy and postpartum periods.

This study examined whether individuals with preexisting type 1 or type 2 diabetes are more likely to experience SMM compared to those without diabetes. Multivariable logistic regression was used to analyze insurance claims from the Arkansas All-Payer Claims Database linked to birth records. SMM and SMM without blood transfusions were evaluated among pregnant individuals with type 1, type 2, or no diabetes. Data were collected from 2017 to 2024 and analyzed in 2025, with a final analytic sample of 176,708 pregnancies.

Individuals with type 1 diabetes had a 2.2 percentage points higher predicted probability of SMM compared to those without type 1 diabetes (p<0.0001) and a 2.0 percentage points higher predicted probability of SMM excluding blood transfusions compared to those without type 1 diabetes (p<0.0001). Individuals with type 2 diabetes had a 1.5 percentage points higher predicted probability of SMM compared to those without type 2 diabetes (p<0.0001) and a 1.3 percentage points higher predicted probability of SMM excluding blood transfusions compared to those without type 2 diabetes (p<0.0001).

Pregnant individuals with preexisting diabetes have an increased risk of severe maternal morbidity, with type 1 diabetes conferring greater risk than type 2 diabetes. Continued efforts to ensure adherence to the clinical standards for comprehensive diabetes management in pregnancy are needed.