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Omalizumab use while Breastfeeding

Drugs containing Omalizumab: Xolair

Medically reviewed by Last updated on Jul 11, 2021.

Omalizumab Levels and Effects while Breastfeeding

Summary of Use during Lactation

Preliminary evidence indicates that the amount in milk is very low. Because omalizumab is a large protein molecule, with a molecular weight of about 150,000 Da, the amount in milk is likely to be 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.[1,2]

Drug Levels

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.[3]

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

Effects 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.[4]

Several case reports of infants being breastfed during maternal omalizumab therapy have been published. No adverse effects have been found.[5-9]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

(Asthma) Benralizumab, Mepolizumab


Türk M, Carneiro-Leao L, Kolkhir P, et al. How to treat patients with chronic spontaneous urticaria with omalizumab: Questions and answers. J Allergy Clin Immunol Pract. 2020;8:113–24. [PubMed: 31374358]
Middleton PG, Gade EJ, Aguilera C, et al. ERS/TSANZ Task Force Statement on the management of reproduction and pregnancy in women with airways diseases. Eur Respir J. 2020;55:1901208. [PubMed: 31699837]
Saito J, Yakuwa N, Sandaiji N, et al. Omalizumab concentrations in pregnancy and lactation: A case study. J Allergy Clin Immunol Pract. 2020;8:3603–4. [PubMed: 32544544]
López Leon, S, Kaufman DG, Howard M, et al. Safety outcomes among infants exposed to omalizumab via breastfeeding: Results from the Xolair Pregnancy Registry (Expect). Pharmacoepidemiol Drug Saf 2019;28 (Suppl 2):374-5. Abstract. doi:10.1002/pds.4864. [CrossRef]
Ensina LF, Cusato-Ensina AP, Camelo-Nunes IC, et al. Omalizumab as third-line therapy for urticaria during pregnancy. J Investig Allergol Clin Immunol. 2017;27:326–7. [PubMed: 29057743]
González-Medina M, Curto-Barredo L, Labrador-Horrillo M, et al. Omalizumab use during pregnancy for chronic spontaneous urticaria (CSU): Report of two cases. J Eur Acad Dermatol Venereol. 2017;31:e245–6. [PubMed: 27868240]
Losappio LM, Mirone C, Schroeder JW, et al. Omalizumab use in chronic spontaneous urticaria during pregnancy and a four years' follow-up: A case report. Case Rep Dermatol. 2020;12:174–7. [PMC free article: PMC7588681] [PubMed: 33173477]
Majou D, Moreira B, Martin C, et al. Safety of omalizumab during pregnancy and breast-feeding with assessment of placental transfer: A case report. Allergy Asthma Immunol Res. 2021;13:515–6. [PMC free article: PMC7984957] [PubMed: 33733644]
Liao SL, Yu M, Zhao ZT, et al. Case report: Omalizumab for chronic spontaneous urticaria in pregnancy. Front Immunol. 2021;12:652973. [PMC free article: PMC8007859] [PubMed: 33796115]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Anti-Allergic Agents

Anti-Asthmatic Agents

Antibodies, Monoclonal

Antibodies, Anti-Idiotypic

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Further information

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