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Mepolizumab Pregnancy and Breastfeeding Warnings

Brand names: Nucala

Medically reviewed by Last updated on Oct 10, 2023.

Mepolizumab Pregnancy Warnings

Animal studies have failed to reveal evidence of fetal harm in doses up to 9 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. Some authorities suggest it should be avoided.

AU TGA pregnancy category: B1
US FDA pregnancy category: Not assigned

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.
-In pregnant patients with poorly or moderately controlled asthma, there is an increased risk of preeclampsia in the mother and prematurity, low birth weight, and small for gestational age in the neonate, asthma should be closely monitored in pregnant women and treatment adjusted as needed.

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

-There is no information regarding this drug on the presence in human milk, the effects on a breastfed infant, or effects on milk production.
-According to some authorities, breastfeeding could be possibly acceptable. Use with caution during breastfeeding, especially while nursing a newborn or preterm infant.

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. Cerner Multum, Inc. UK Summary of Product Characteristics.
  2. Cerner Multum, Inc. Australian Product Information.
  3. Product Information. Nucala (mepolizumab). GlaxoSmithKline. 2015.

References for breastfeeding information

  1. Cerner Multum, Inc. UK Summary of Product Characteristics.
  2. Cerner Multum, Inc. Australian Product Information.
  3. United States National Library of Medicine. Toxnet. Toxicology Data Network. 2013.
  4. Product Information. Nucala (mepolizumab). GlaxoSmithKline. 2015.

Further information

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