What types of insulin are safe to use during pregnancy?

Safe Insulin Types During Pregnancy

Human insulin preparations are the preferred and safest option for managing diabetes during pregnancy, as none of the currently available human insulin preparations have been demonstrated to cross the placenta. 1, 2

Human Insulins vs. Insulin Analogs

Human Insulins (First-Line Options)

• Human insulins (regular and NPH) are considered safe during pregnancy as they do not cross the placenta 1, 2
• NPH insulin is a well-established option for basal insulin needs during pregnancy 2
• Regular human insulin can be used for bolus/mealtime coverage 2

Rapid-Acting Insulin Analogs

• Insulin aspart has been studied in pregnancy and has FDA pregnancy category B classification 3
• Insulin lispro has also been shown to be safe in pregnant women with diabetes 4
• Both aspart and lispro have not demonstrated adverse maternal or fetal effects during pregnancy 5

Long-Acting Insulin Analogs

• Insulin detemir has been reclassified as FDA pregnancy category B and is considered safe for use in pregnancy 4
• Insulin glargine has limited but generally reassuring safety data in pregnancy 4
• Insulin glargine's FDA label notes that "published studies with use of insulin glargine during pregnancy have not reported a clear association with insulin glargine and adverse developmental outcomes" 6
• There is insufficient data on insulin degludec and glulisine in pregnancy, making them less preferred options 7, 5

Insulin Management During Pregnancy

Physiological Considerations

• Early pregnancy is characterized by enhanced insulin sensitivity, which may require lower insulin doses 2
• Insulin requirements typically increase linearly from around 16 weeks gestation 7, 2
• Insulin needs often double compared to pre-pregnancy requirements by the third trimester 2
• Insulin requirements drop rapidly with delivery of the placenta 1, 2

Administration Methods

• Both multiple daily injections and insulin pump technology are reasonable delivery strategies during pregnancy 1, 2
• Neither method has been shown to be superior to the other during pregnancy 1

Special Considerations

Hypoglycemia Risk

• Pregnant individuals with type 1 diabetes have an increased risk of hypoglycemia in the first trimester 1, 2
• Altered counter-regulatory responses during pregnancy may decrease hypoglycemia awareness 1
• Education about hypoglycemia prevention, recognition, and treatment is essential 1

Clinical Management

• Due to the complexity of insulin management in pregnancy, referral to a specialized center offering team-based care is recommended when available 1, 2
• Pregnant individuals with diabetes should be prescribed low-dose aspirin 100–150 mg/day starting at 12 to 16 weeks of gestation to lower the risk of preeclampsia 1, 2

Common Pitfalls to Avoid

• Failing to adjust insulin doses frequently throughout pregnancy as requirements change 2
• Using oral antidiabetic agents as first-line therapy instead of insulin 1
• Not providing adequate education about hypoglycemia management, which is especially important during pregnancy 1
• Overlooking the rapid drop in insulin requirements immediately after delivery 1, 2