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Insulin regular Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Mar 27, 2023.

Insulin regular is also known as: Humulin R, Humulin R U-500 (Concentrated), Humulin R U-500 KwikPen, Iletin II Regular Pork, Iletin Regular, Myxredlin, Novolin R, Novolin R Innolet, Novolin R PenFill, ReliOn/Humulin R, ReliOn/Novolin R, Velosulin BR

Insulin regular Pregnancy Warnings

Use is considered acceptable

AU TGA pregnancy category: Not Assigned
US FDA pregnancy category: Not Assigned (U-100); Category B (U-500)

Risk Summary: No association with major birth defects, miscarriage, or adverse maternal or fetal outcomes has been observed over the years this drug has been used; risks are associated with poorly controlled diabetes in pregnancy.

-Good metabolic control before conception and throughout pregnancy is essential for patients with diabetes or a history of gestational diabetes to minimize disease-associated maternal and embryo/fetal risks.

Pregnancies complicated by hypoglycemia and hyperglycemia pose an increased risk of birth defects, pregnancy loss, or other adverse events. The estimated background risk of major birth defects in women with pre-gestational diabetes with a HbA1c greater than 7 is is 6% to 10% and in women with a HbA1C greater than 10, has been reported to be as high as 20% to 25%. The estimated risk in women with diabetes is unknown, but the estimated risk in the general population (US) has been estimated at 2% to 4%. Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, pre-eclampsia, spontaneous abortions, preterm delivery, stillbirth, and delivery complications; fetal risk is increased for major birth defects, stillbirth, and macrosomia-related mortality. Insulin requirements may decrease during the first trimester; generally increase during the second and third trimesters, and rapidly decline after delivery. Careful monitoring of glucose control is essential.

AU TGA pregnancy category: Not assigned; this class of drugs is generally exempt from pregnancy classification.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

See references

Insulin regular Breastfeeding Warnings

Exogenous insulins, including the newer biosynthetic insulins (i.e. aspart, detemir, glargine, glulisine, lispro) appear to be excreted into breast milk. Insulin is a protein that is inactivated if taken by mouth. If absorbed, it would be destroyed in the digestive tract of the infant.

Lactation onset occurs later in women with type 1 diabetes, and there is an even greater delay in those with poor glucose control. However, once established lactation persists as long in mothers with diabetes as in mothers without. Insulin requirements are generally lower in women who breastfeed, most likely due to glucose being used for milk production. In a small well controlled study in breastfeeding women with type 1 diabetes using continuous subcutaneous insulin infusion, basal and total daily insulin requirements were found to be 0.21 units/kg and 0.56 units/kg , respectively compared to 0.33 units/kg and 0.75 units/kg per day in similar women who did not breastfeed.

Use is considered acceptable

Excreted into human milk: Yes

Breast-feeding mothers may require adjustments in insulin dose.

See references

References for pregnancy information

  1. "Product Information. Humulin R (insulin regular)." Lilly, Eli and Company (2002):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. "Product Information. NovoLIN R (insulin regular)." Novo Nordisk Pharmaceuticals Inc (2015):
  5. Blumer I, Hadar E, Hadden DR, et al. "Diabetes and pregnancy: an endocrine society clinical practice guideline." J Clin Endocrinol Metab 98 (2013): 2013-465

References for breastfeeding information

  1. "Product Information. Humulin R (insulin regular)." Lilly, Eli and Company (2002):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. United States National Library of Medicine "Toxnet. Toxicology Data Network." (2013):
  5. "Product Information. NovoLIN R (insulin regular)." Novo Nordisk Pharmaceuticals Inc (2015):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.