Can you take emicizumab 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.
A low level of emicizumab was found in the milk of 2 women. The drug is likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal. One infant was breastfed for 2 months starting at 4 months of age during maternal therapy with no obvious adverse reaction. Waiting for at least 2 weeks postpartum to resume therapy may minimize transfer to the infant.
Quoted from Emicizumab — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised July 15, 2026.
How much emicizumab gets into breastmilk
Maternal Levels. A woman with severe hemophilia A received emicizumab every 4 weeks (dose not stated, but probably 6 mg/kg) throughout pregnancy and postpartum as well as recombinant factor VIIa (NovoSeven) 90 mcg/kg every 2 hours initially with a gradually increasing dosage interval postpartum for severe bleeding. A milk sample taken at an unreported time contained 38 mg/L of emicizumab.
Milk samples were collected from a woman who developed acquired hemophilia A four months after delivery. She was treated with emicizumab in a loading doses of 600 mg (6 mg/kg) and 300 mg (3 mg/kg) subcutaneously on days 3 and 4 of hospitalization, respectively, followed by a maintenance dose of 150 mg on day 10 and continued weekly thereafter. Emicizumab was first detected on day 4 of hospitalization at concentrations below the lower limit of quantification (LLOQ) of 10 mg/L. Milk concentrations increased over time and exceeded the LLOQ on day 6. By day 8, the mean concentration reached 20.1 mg/L in breastmilk. Anti-FVIII IgG and IgA were not detected in breastmilk samples.
Infant Levels. A woman with severe hemophilia A was receiving emicizumab every 4 weeks (dose not stated, but probably 6 mg/kg) throughout pregnancy and postpartum as well as recombinant factor VIIa (NovoSeven) 90 mcg/kg every 2 hours initially with a gradually increasing dosage interval postpartum for severe bleeding. A serum sample taken from the infant at an unreported time contained 106 mg/L of emicizumab, probably obtained transplacentally.
What has been seen in breastfed infants
A woman who developed acquired hemophilia A four months after delivery. She was treated with emicizumab in a loading doses of 600 mg (6 mg/kg) and 300 mg (3 mg/kg) subcutaneously on days 3 and 4 of hospitalization, respectively, followed by a maintenance dose of 150 mg on day 10 and continued weekly thereafter. Her infant was exclusively breastfed for six months and demonstrated normal weight gain without failure to thrive. No signs of bleeding or thromboembolic events were observed at any time.
Effects on milk supply
Relevant published information was not found as of the revision date.
Frequently asked questions
Can you take emicizumab while breastfeeding?
A low level of emicizumab was found in the milk of 2 women. 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.
Does emicizumab pass into breastmilk?
LactMed's measured drug levels for emicizumab are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking emicizumab?
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 emicizumab
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.