Class RF: retinopathy and nephropathy Class H: ischemic heart disease Class T: prior kidney transplant An early age of onset or long-standing disease comes with greater risks, hence the first three subtypes. See also Diabetes mellitus Gestational diabetes Pregnancy Footnotes External links CDC's National Center on Birth Defects and Developmental Disabilities Pathology of pregnancy, childbirth and the puerperium Diabetes Health issues in pregnancy