Can you take omalizumab while breastfeeding?
What LactMed says
The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.
Preliminary evidence indicates that the amount of omalizumab in milk is very low. It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal. Many infants have been breastfed during maternal omalizumab therapy, with no increase in infectious complications. Omalizumab is considered acceptable to use during breastfeeding. Waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.
Quoted from Omalizumab — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised February 15, 2026.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of omalizumab. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
How much omalizumab gets into breastmilk
Maternal Levels. A woman received omalizumab 5 weekly doses of omalizumab 150 mg subcutaneously during pregnancy until 28 weeks of gestation. Breastmilk omalizumab levels were determined on days 4 and 5 postpartum, which were 85 and 86 days after the last dose of omalizumab. Four concentrations in milk were below 2 mcg/L and one was just over 8 mcg/L.
Infant Levels. Relevant published information was not found as of the revision date.
What has been seen in breastfed infants
A manufacturer-based omalizumab pregnancy registry has followed pregnant and nursing mothers for several years. Of 230 infants followed, 154 were breastfed while their mothers were taking omalizumab. Another 32 were breastfed without being exposed to the drug in milk and 44 were not breastfed. No difference in serious adverse events were seen among the three groups of infants. Infections occurred at a similar rate in all groups.
Several case reports of infants being breastfed during maternal omalizumab therapy have been published. No adverse effects have been found.
A woman with cystic fibrosis and severe, persistent asthma was started on omalizumab 600 mg subcutaneously every 2 weeks. She was maintained on this regimen for 5 years when she became pregnant. The regimen was continued during pregnancy and postpartum. She breastfed (extent not stated) for 8 months. At 10 months of age, her infant was in good health.
A retrospective study in a hospital in China found 5 infants who were breastfed during maternal omalizumab use at a dosage of 150 to 300 mg every 4 weeks. No adverse effects were seen in the infants.
Effects on milk supply
Relevant published information was not found as of the revision date.
Frequently asked questions
Can you take omalizumab while breastfeeding?
Preliminary evidence indicates that the amount of omalizumab in milk is very low. The full record is quoted on this page, and the decision is one to make with the person who prescribed it — LactMed itself states it is not a substitute for professional judgement.
What can I take instead of omalizumab while breastfeeding?
LactMed lists Benralizumab, Mepolizumab as alternate drugs to consider. That is the database's own list for this drug — whether any of them suits you depends on what you are treating.
Does omalizumab pass into breastmilk?
LactMed's measured drug levels for omalizumab are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking omalizumab?
LactMed does not frame its records that way — it reports measured drug levels in milk and what has been observed in breastfed infants, which is what this page quotes. "Pump and dump" advice for a specific drug and dose should come from your clinician or a pharmacist, not from a general rule.
More on omalizumab
LactMed states that the information it presents is not a substitute for professional judgement, and that you should consult your healthcare provider for breastfeeding advice related to your particular situation. Nothing on this page is medical advice.