Overt Diabetes and Pregestational Type 2 Diabetes in Pregnancy

Key Definitional Differences and Clinical Risk Profile

Pregestational type 2 diabetes is type 2 diabetes diagnosed before pregnancy, allowing for preconception optimization, as recommended by the American Diabetes Association 1, 2

Both overt diabetes and pregestational type 2 diabetes confer significantly greater risks than gestational diabetes mellitus (GDM), including spontaneous abortion 1, fetal anomalies (anencephaly, microcephaly, congenital heart disease, caudal regression) 2, preeclampsia 2, macrosomia 2, intrauterine fetal demise 2, and neonatal hypoglycemia and hyperbilirubinemia 2
Type 2 diabetes carries risks for associated hypertension and comorbidities that may be as high or higher than type 1 diabetes, even with better glycemic control and shorter apparent duration, according to the American College of Obstetricians and Gynecologists 3, 4, 5

The American Diabetes Association recommends an A1C target during pregnancy of <6% if achievable without significant hypoglycemia 1
For preconception planning in known type 2 diabetes, the American College of Obstetricians and Gynecologists recommends a target A1C <6.5% (48 mmol/mol) to minimize congenital anomaly risk 2

Insulin is the preferred agent for both overt diabetes and pregestational type 2 diabetes during pregnancy, as recommended by the American Diabetes Association 6, 3, 4, 5
Type 2 diabetes often requires much higher insulin doses than type 1 diabetes, sometimes necessitating concentrated insulin formulations, according to the Endocrine Society 3, 4, 5

The American College of Obstetricians and Gynecologists recommends weight gain for women with type 2 diabetes: overweight (BMI 25-29.9): 15-25 lb, obese (BMI ≥30): 10-20 lb 3, 4, 8, 5, 6

The American College of Obstetricians and Gynecologists recommends low-dose aspirin 100-150 mg/day for women with type 2 diabetes or overt diabetes to reduce preeclampsia risk 8

Women with pregestational type 2 diabetes require baseline ophthalmology exam in first trimester and monitoring every trimester as indicated by retinopathy degree, as recommended by the American Diabetes Association 1
Home ketone strips and diabetic ketoacidosis education are also recommended, although the risk is lower than type 1 diabetes, according to the Endocrine Society 3, 4, 5

The American College of Obstetricians and Gynecologists recommends stopping immediately at conception or avoiding in sexually active women not using reliable contraception: ACE inhibitors, angiotensin receptor blockers, and statins 1, 2, 8, 6, 5

Referral to specialized centers offering team-based care is recommended when available, as suggested by the American Diabetes Association 8