What antidiabetic medications should be avoided in pregnancy?

Antidiabetic Medications to Avoid in Pregnancy

Most oral antidiabetic agents should be discontinued before conception or as soon as pregnancy is confirmed, with the notable exceptions of metformin and glyburide, which may be continued under specific circumstances. 1

Medications That Must Be Avoided

ACE Inhibitors and Statins (Critical to Discontinue)

• ACE inhibitors and angiotensin receptor blockers (ARBs) are absolutely contraindicated in pregnancy due to associations with fetal renal anomalies, oligohydramnios, and fetal death 1
• Statins must be discontinued in all sexually active women of childbearing age who are not using reliable contraception 1, 2
• These medications are commonly prescribed alongside diabetes medications for cardiovascular protection but pose severe teratogenic risks 1

Oral Antidiabetic Agents (General Approach)

• The majority of oral antidiabetic agents should be discontinued because they either cross the placenta or lack adequate long-term safety data 1
• The American Diabetes Association guidelines state that most oral agents should be stopped and insulin initiated 1

Acceptable Oral Agents (Limited Use)

Metformin

• May be continued during the preconception period and potentially throughout pregnancy 1
• Does not increase fetal anomalies and may reduce neonatal hypoglycemia and maternal weight gain 3
• Crosses the placenta but has no serious safety concerns in available studies 3

Glyburide (Glibenclamide)

• Widely used in pregnancy alongside insulin and metformin 1
• More effective than metformin at lowering blood glucose with lower treatment failure rates 3
• Some studies report higher rates of preeclampsia, neonatal jaundice, macrosomia, and neonatal hypoglycemia compared to insulin 3

First-Line Treatment: Insulin

Insulin remains the gold standard and only FDA-approved medication for diabetes management in pregnancy 4, 3

• Has the greatest evidence for safety and efficacy 4
• Should be initiated when lifestyle modifications fail to achieve glycemic targets 3
• Both injection therapy and insulin pump therapy are effective approaches 2

Critical Preconception Medication Review

When counseling women with diabetes planning pregnancy:

• Review all medications for teratogenic potential including ACE inhibitors, ARBs, statins, and atenolol 1
• Discontinue potentially harmful agents before conception in sexually active women not using reliable contraception 1
• Aim for hemoglobin A1C <7% before conception and <6% during pregnancy to minimize risk of congenital anomalies 1, 2

Common Pitfalls to Avoid

• Do not continue ACE inhibitors or ARBs even if blood pressure control is suboptimal—switch to methyldopa, labetalol, or long-acting nifedipine 5
• Avoid atenolol for hypertension management as it is associated with fetal growth restriction and lower birth weight 1, 5
• Do not use chronic diuretics as they restrict maternal plasma volume and may reduce uteroplacental perfusion 6
• Ensure glucagon availability for all women on insulin therapy due to increased risk of severe hypoglycemia during pregnancy 2