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Mepolizumab Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Oct 20, 2020.

Mepolizumab is also known as: Nucala

Mepolizumab Pregnancy Warnings

Animal studies have failed to reveal evidence of fetal harm in doses up to 30 times the maximum recommended human dose. This drug crossed the placental barrier in animal models and is predicted to have its greatest effect during the second and third trimesters. There are no controlled data in human pregnancy.

To monitor the outcomes of pregnant women exposed to this drug, a pregnancy registry has been established. Physicians are encouraged to register patients and pregnant women are encouraged to register themselves by calling 1-877-311-8972.

AU TGA pregnancy category B1: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.

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.

This drug should be used during pregnancy only if the benefit outweighs the risk to the fetus.

AU TGA pregnancy category: B1
US FDA pregnancy category: Not formally assigned to a pregnancy category.

Risk summary: Insufficient data exist on the use of this drug in pregnant women to inform on drug-associated risk.

-A pregnancy registry is available.

See references

Mepolizumab Breastfeeding Warnings

A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Unknown
Excreted into animal milk: Yes

-The effects in the nursing infant are unknown.

Animal studies have shown that this drug is excreted in maternal milk at concentrations of less than 0.5% of those detected in plasma. This drug is a monoclonal antibody (IgG1 kappa) and immunoglobulin G is present in human milk; however, there are no data regarding the presence of this drug in human milk.

See references

References for pregnancy information

  1. "Product Information. Nucala (mepolizumab)." GlaxoSmithKline, Research Triangle Park, NC.
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0

References for breastfeeding information

  1. "Product Information. Nucala (mepolizumab)." GlaxoSmithKline, Research Triangle Park, NC.
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  4. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL:" ([cited 2013 -]):

Further information

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