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Peginterferon Alfa use while Breastfeeding

Medically reviewed by Last updated on Mar 2, 2022.

Peginterferon Alfa Levels and Effects while Breastfeeding

Summary of Use during Lactation

Although no information is available on peginterferon alfa in breastmilk, the levels of conventional interferon alfa in breastmilk are minuscule. In addition, because interferon is poorly absorbed orally, it is not likely to reach the bloodstream of the infant. Polyethylene glycol is not excreted into breastmilk.[1] It is unlikely that peginterferon alfa use by a nursing mother presents any serious risk to the breastfed infant. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of the related endogenous interferon-gamma by an average about 10%.[2]

For use in treating maternal hepatitis B, no differences exist in infection rates between breast-fed and formula-fed infants born to hepatitis B-infected women, as long as the infant receives hepatitis B immune globulin and hepatitis B vaccine at birth. Mothers with hepatitis B are encouraged to breastfeed their infants after their infants receive these preventative measures.[3,4]

Drug Levels

No information is available specifically on peginterferon alfa. However, data are available on non-pegylated interferon alfa.

Maternal Levels. Two mothers taking interferon alfa had milk levels measured. One mother taking 8 million units three times a week had a milk level of 1400 units/L and another taking 8 million units daily had a milk level of 6000 units/L. Both levels were apparently measured immediately postpartum (in colostrum), but the time since the previous dose was not stated.[5]

An intravenous dose of 30 million units of interferon alfa-2B in one woman resulted in a peak milk level of 1551 International Units/L which was a slight increase over two baseline levels prior to the dose which averaged 1072 International Units/L. By 12 hours after the dose, milk interferon levels were lower than baseline.[6]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

One infant was born to a mother who received 3 million units of interferon alfa-2a subcutaneously 3 times weekly during pregnancy and postpartum for essential thrombocytopenia. Her infant was breastfed for 2 weeks postpartum before bilateral mastitis caused the mother to terminate nursing. The infant reportedly thrived, although specific measures were not mentioned.[7]

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

Alternate Drugs to Consider

(Hepatitis B) Lamivudine, Tenofovir; (Hepatitis C) Interferon Alfa, Interferon Alfacon-1


Clowse ME, Förger F, Hwang C, et al. Minimal to no transfer of certolizumab pegol into breast milk: Results from CRADLE, a prospective, postmarketing, multicentre, pharmacokinetic study. Ann Rheum Dis. 2017;76:1890–6. [PMC free article: PMC5705850] [PubMed: 28814432]
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. [PubMed: 21330996]
Visvanathan K, Dusheiko G, Giles M, et al. Managing HBV in pregnancy. Prevention, prophylaxis, treatment and follow-up: Position paper produced by Australian, UK and New Zealand key opinion leaders. Gut. 2016;65:340–50. [PubMed: 26475631]
Dionne-Odom J, Tita AT, Silverman NS. #38: Hepatitis B in pregnancy screening, treatment, and prevention of vertical transmission. Am J Obstet Gynecol. 2016;214:6–14. [PubMed: 26454123]
Haggstrom J, Adriansson M, Hybbinette T, et al. Two cases of CML treated with alpha-interferon during second and third trimester of pregnancy with analysis of the drug in the new-born immediately postpartum. Eur J Haematol 1996;57:101-2. Letter. PMID: 8698119. [PubMed: 8698119]
Kumar AR, Hale TW, Mock RE. Transfer of interferon alfa into human breast milk. J Hum Lact. 2000;16:226–8. [PubMed: 11153157]
Williams JM, Schlesinger PE, Gray AG. Successful treatment of essential thrombocythaemia and recurrent abortion with alpha interferon. Br J Haematol. 1994;88:647–8. [PubMed: 7819084]

Substance Identification

Substance Name

Peginterferon Alfa

CAS Registry Number

198153-51-4; 215647-85-1

Drug Class

Breast Feeding


Antiviral Agents

Biological Response Modifiers

Antineoplastic Agents

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Further information

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