Preconception Care for Women with Diabetes

Medications to Discontinue

The American Diabetes Association recommends that women with diabetes planning pregnancy must immediately discontinue ACE inhibitors and ARBs before conception, as these medications are teratogenic and contraindicated in pregnancy, due to associations with fetal renal anomalies, oligohydramnios, and fetal death 1, 2, 3
Statins are pregnancy category X and must be stopped in all sexually active women of childbearing age who are not using reliable contraception, as recommended by the American College of Obstetricians and Gynecologists 1, 2, 4

The American College of Obstetricians and Gynecologists suggests that metformin may be continued during the preconception period and potentially throughout pregnancy, as it does not increase fetal anomalies and may reduce neonatal hypoglycemia and maternal weight gain 3, 5
Glyburide is widely used in pregnancy alongside insulin and metformin, and is more effective than metformin at lowering blood glucose, though it may have higher treatment failure rates, according to the American Diabetes Association 3

The American Heart Association recommends switching to methyldopa, labetalol, or long-acting nifedipine for blood pressure control, with a target blood pressure of 110-135/85 mmHg to reduce risk of accelerated maternal hypertension while minimizing impaired fetal growth 6, 3, 7
The American College of Obstetricians and Gynecologists suggests starting low-dose aspirin 100-150 mg/day at 12 to 16 weeks of gestation to reduce the risk of preeclampsia in women with diabetes 1, 6, 7

The American Diabetes Association recommends achieving A1C <6.5% before conception, ideally <6%, to minimize congenital anomalies, preeclampsia, and other complications, and using effective contraception until metabolic optimization is achieved 7, 5, 8
The Endocrine Society suggests prescribing prenatal vitamins with at least 400 mcg of folic acid before conception, and screening for diabetic complications including retinopathy, nephropathy, and neuropathy before conception 1, 2, 8

The American College of Obstetricians and Gynecologists recommends that women with preexisting diabetes should be managed in a multidisciplinary clinic including an endocrinologist, maternal-fetal medicine specialist, registered dietitian nutritionist, and diabetes educator when available, and that medication review must be immediate to avoid exposure to teratogenic medications 1, 2, 3, 7, 8

The American Diabetes Association recommends achieving glycemic control with HbA1c <6.5% before conception as the most important diabetes-specific component of preconception care, with the strongest evidence for reducing congenital anomalies and adverse pregnancy outcomes 9, 10, 11, 12
Achieving HbA1c <6.5% before conception is directly associated with the lowest risk of congenital anomalies, preeclampsia, macrosomia, and preterm birth 9, 10, 11, 12

Organogenesis occurs primarily at 5-8 weeks of gestation, when most women don't yet know they are pregnant 9, 11, 13
The risk of diabetic embryopathy is directly proportional to HbA1c elevations during the first 10 weeks of pregnancy 9, 11, 13

Preconception care that achieves optimal glycemic control reduces risks of birth defects, preterm delivery, perinatal mortality, small-for-gestational-age births, and neonatal intensive care unit admissions 10, 12

Effective contraception must be prescribed and used until HbA1c is optimized 9, 10, 11, 12
Target HbA1c <6.5%, ideally as close to 6% as possible without significant hypoglycemia 9, 10, 11, 12
Refer to a multidisciplinary clinic including endocrinologist, maternal-fetal medicine specialist, registered dietitian, and diabetes educator 9, 10, 11, 12
Prescribe prenatal vitamins with 400-800 mcg folic acid and 150 mcg potassium iodide 12
Screen for diabetic complications: retinopathy, nephropathy, neuropathy 9, 11
Perform dilated eye examination 10, 11, 12

The American Diabetes Association recommends targeting an A1C <6.5% before conception, ideally as close to 6% as possible, without significant hypoglycemia, to minimize the risk of diabetic embryopathy 14
Daily glucose targets should be: fasting 70-95 mg/dL, preprandial 60-99 mg/dL, 1-hour postprandial 110-140 mg/dL, and 2-hour postprandial 100-120 mg/dL 14
Monthly A1C monitoring is recommended during preconception optimization 14

A dilated eye examination should be performed immediately before conception, and repeated every trimester during pregnancy and 1-year postpartum, as pregnancy increases the risk of development and/or progression of diabetic retinopathy 15
Baseline urine albumin-to-creatinine ratio and serum creatinine should be obtained to assess renal function 14
Prenatal vitamins with at least 400 mcg folic acid should be prescribed immediately, ideally 400-800 mcg, to minimize the risk of fetal malformations 14

Referral to a multidisciplinary preconception clinic, including an endocrinologist or diabetologist, maternal-fetal medicine specialist, registered dietitian nutritionist, diabetes educator, and ophthalmologist, is recommended 14
A registered dietitian can help establish a food plan, insulin-to-carbohydrate ratios, and weight gain goals, and provide counseling on consistent carbohydrate intake to match insulin dosing and avoid hyperglycemia or hypoglycemia 15

Effective contraception should be prescribed immediately and used until A1C <6.5% is achieved, as periconceptional hyperglycemia is directly related to congenital malformations 14
Conception should not be attempted until A1C <6.5% is documented, which may take 3-6 months of intensive management 14