Table 1.

Criteria used to identify mothers with type 1 and type 2 diabetes and GDM

Criteria	Type 1 diabetes	Type 2 diabetes	GDM
Inclusion	Insulin dispensed at least 3 times in the year before pregnancy AND insulin dispensed at least once from 6 months to 1 year after delivery	Oral glucose-lowering agents or insulin dispensed at least 3 times in the year before pregnancy AND at least one of the following criteria: - an HbA1c assay performed or glucose strips dispensed in the year before pregnancy - long-term disease status for diabetes before pregnancy - oral glucose-lowering agents or insulin dispensed at least once during pregnancy or in the year after delivery	At least one of the following criteria: - insulin dispensed at least once during pregnancy - at least 200 glucose strips dispensed during pregnancy on at least 2 different occasions - a diagnosis of diabetes recorded during the delivery admission (ICD-10 codes E10–E14, O240–O244, O249)a
Exclusion	Oral glucose-lowering agents dispensed in the year before pregnancy or the year after delivery	Meeting the definition of type 1 diabetes	Long-term disease status for diabetes before pregnancy Insulin or oral glucose-lowering agents dispensed at least once during the year before pregnancy

^aICD-10 codes include both GDM and pregestational diabetes to correct coding errors (GDM that may have been coded as pregestational diabetes), as the sensitivity for GDM observed in the PMSI database was only 73% [16]