Type 1 diabetes (due to b-cell destruction, usually leading to absolute insulin
deficiency)
2. Type 2 diabetes (due to a progressive insulin secretory defect on the background
of insulin resistance)
3. Gestational diabetes mellitus (GDM) (diabetes diagnosed in the second or third
trimester of pregnancy that is not clearly overt diabetes)
4. Specific types of diabetes due to other causes, e.g., monogenic diabetes syndromes
(such as neonatal diabetes and maturity-onset diabetes of the young [MODY]), diseases
of the exocrine pancreas (such as cystic fibrosis), and drug- or chemical-induced
diabetes (such as in the treatment of HIV/AIDS or after organ transplantation)