Long-Acting Insulin Safety During Pregnancy
Long-acting insulin is safe and recommended during pregnancy for women with diabetes who require insulin therapy. 1, 2
Safety Profile of Long-Acting Insulin in Pregnancy
- The FDA label for insulin glargine (a common long-acting insulin) states that published studies have not reported a clear association between insulin glargine and adverse developmental outcomes during pregnancy 2
- The American Diabetes Association's 2024 Standards of Care explicitly states that insulin is the preferred agent for managing both type 1 and type 2 diabetes during pregnancy 1
- Animal reproduction studies with insulin glargine at doses 10-50 times the human subcutaneous dosage did not generally show effects different from regular human insulin 2
Clinical Recommendations for Long-Acting Insulin Use
- Insulin does not cross the placenta, making it the safest option for blood glucose management during pregnancy 1
- Both multiple daily injections (which typically include long-acting insulin) and insulin pump therapy are considered reasonable delivery strategies for insulin during pregnancy 1
- For pregnant women with type 2 diabetes, insulin is specifically identified as the preferred treatment agent 1
Administration Considerations
For pregnant women using long-acting insulin:
The abdomen remains a safe site for insulin administration throughout pregnancy, with some adjustments as pregnancy progresses 1:
- First trimester: No change in insulin site or technique needed
- Second trimester: Entire abdomen can be used with properly raised skinfolds
- Third trimester: Lateral abdomen with properly raised skinfolds, or thigh/upper arm/buttock as alternatives
A 4-mm pen needle is recommended for pregnant women due to thinning of abdominal fat from uterine expansion 1
Important Precautions
- Pregnant women have an increased risk of hypoglycemia, particularly in the first trimester, and altered counter-regulatory responses that may decrease hypoglycemia awareness 1
- Education for patients and family members about prevention, recognition, and treatment of hypoglycemia is essential 1
- Insulin requirements change throughout pregnancy and drop rapidly with delivery of the placenta, necessitating frequent titration and monitoring 1
Comparison with Other Medications
- Oral hypoglycemic agents like metformin and sulfonylureas cross the placenta and have shown concerning long-term effects on offspring 1
- Metformin exposure has been associated with higher BMI and increased obesity in offspring in follow-up studies 1
- Sulfonylureas cross the placenta at 50-70% of maternal levels and have been associated with increased neonatal hypoglycemia 1
Long-acting insulin remains the gold standard therapy for diabetes management during pregnancy, offering the best balance of glycemic control and safety for both mother and fetus.