Interferon Beta use while Breastfeeding
Interferon Beta Levels and Effects while Breastfeeding
Summary of Use during Lactation
The levels of interferon beta-1a in breastmilk are minuscule. In addition, because interferon is poorly absorbed orally, it is not likely to reach the bloodstream of the infant. A small number of nursing mothers receiving interferon beta-1a while partially breastfeeding their infants and one woman exclusively breastfed her infant while taking interferon beta-1b and reported no adverse effects. A French consensus group of neurologists concluded that interferon beta can be used during breastfeeding. No special precautions appear to be required during breastfeeding while using interferon beta. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous interferon-gamma by an average about 10%. 
Maternal Levels. Six women were receiving interferon beta-1a (Avonex, Biogen) 30 mcg intramuscularly once weekly for multiple sclerosis. Milk samples from both breasts were collected after pumping with an electric breast pump at 8 times after a dose at baseline and at 7 other times during the first 72 hours after a dose. Samples were combined and analyzed for interferon beta-1a. About half of the samples had undetectable (<20 ng/L) amounts of drug. The highest concentrations were found at 1 or 4 hours after the dose in all women. The highest concentration found was 171 ng/L in one woman. Using this value, the authors estimated that the maximum weight-adjusted dosage that an infant would receive is 0.006% of the maternal dose.
Infant Levels. Relevant published information was not found as of the revision date.
Effects in Breastfed Infants
Six women had been receiving interferon beta-1a (Avonex, Biogen) 30 mcg intramuscularly once weekly for multiple sclerosis for months to years. None of the mothers noticed any adverse effects in their breastfed infants.
A woman received interferon beta-1b (Betaferon, BayerHealthCare; dosage unspecified) for multiple sclerosis throughout pregnancy. She continued the drug while she exclusively breastfed her infant. At 5 months of age, the infant was monitored regularly by a physician and was developing well with no abnormalities.
One mother received interferon beta-1a for multiple sclerosis during pregnancy and postpartum. All of their infants were exclusively breastfed for 6 months and no noticeable problems were reported in any of them.
In data collected from 4 countries, 17 women received interferon and 41 women received glatiramer during pregnancy and postpartum for treatment of multiple sclerosis. Of these, 63% breastfed (extent not stated) their infants for a mean of 8.8 months. No mention was made of adverse reactions in breastfed infants.
Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.
Alternate Drugs to Consider
(Multiple Sclerosis) Glatiramer Acetate, (Hepatitis C) Interferon Alfa, Interferon Alfacon
1. Bodiguel E, Bensa C, Brassat D et al. [Multiple sclerosis and pregnancy]. Rev Neurol (Paris). 2014;170:247-65. PMID: 24684929
2. Ewaschuk JB, Unger S, O'Connor DL et al. Effect of pasteurization on selected immune components of donated human breast milk. J Perinatol. 2011;31:593-8. PMID: 21330996
3. Hale TW, Siddiqui AA, Baker TE. Transfer of interferon beta-1a into human breastmilk. Breastfeed Med. 2012;7:123-5. PMID: 21988602
4. Rockhoff M, Hellwig K. [Family planning and interferon (beta)-1b - A case report of successful hormonal stimulation, pregnancy and breast-feeding under interferon (beta)-1b]. Aktuel Neurol Suppl. 2012;39 (Suppl 1):S49-S51.
5. Hellwig K, Gold R. Glatiramer acetate and interferon-beta throughout gestation and postpartum in women with multiple sclerosis. J Neurol. 2011;258:502-3. PMID: 20878174
6. Fragoso YD, Boggild M, Macias-Islas MA et al. The effects of long-term exposure to disease-modifying drugs during pregnancy in multiple sclerosis. Clin Neurol Neurosurg. 2013;115:154-9. PMID: 22633835
Interferon Beta Identification
CAS Registry Number
LactMed Record Number
Last Revision Date
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