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Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.

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Drugs and Lactation Database (LactMed) [Internet].

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Last Revision: April 19, 2021.

Estimated reading time: 4 minutes

CASRN: 815610-63-0

Drug Levels and Effects

Summary of Use during Lactation

Ustekinumab is usually either not detectable in breastmilk or detectable at very low levels in breastmilk. It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal. If ustekinumab is required by the mother, it is not a reason to discontinue breastfeeding and some experts and professional organizations consider it acceptable[1] in nursing women with psoriasis.[1-4] Until more data become available, ustekinumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.[5]

Ustekinumab is a human immunoglobulin G1 (IgG1) kappa antibody. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous immunoglobulin G by up to 79%.[6-8] A study of 67 colostrum samples that underwent Holder pasteurization found that IgG amounts decreased by 34 to 40%. Specific IgG subclasses decreased by different amounts, with IgG1 activity decreasing by about 37%.[8] None of the studies measured IgG activity. Ustekinumab is unstable in breastmilk, with up to a 26% decrease in drug concentration when stored for 24 hours at room temperature.[9]

Drug Levels

Maternal Levels. In a multi-center study of women with inflammatory bowel disease in pregnancy (the PIANO registry), 6 women receiving ustekinumab provided milk samples at 1, 12, 24, and 48 hours after drug administration. Some also provided samples at 72, 96, 120, and 168 hours after drug administration. Four of the women had detectable (>0.01 mg/L) ustekinumab levels in milk. Peak concentrations in breastmilk ranged from 0.72 to 1.57 mg/L and occurred at 12 to 72 hours after the dose. Only 3 of the women had a detectable concentration in milk beyond 48 hours.[10]

A woman with treatment-refractory Crohn’s disease was treated during pregnancy with ustekinumab until the third trimester. It was reinitiated 7 weeks postpartum with a loading dose of 390 mg intravenously, then 90 mg every 8 weeks. A breastmilk sample taken 16 weeks after the dose was 3.2 mg/L. After the third dose, breastmilk levels of ustekinumab were 0.82 mg/L within the first day after the dose, 0.18 mg/L at 3 weeks after the third dose and 0.16 mg/L at 4 weeks after the third dose.[9]

Three mothers taking ustekinumab for Crohn’s disease had breastmilk levels of ustekinumab measured 1 hour after a dose and sequentially for up to 2 weeks after the dose. In one patient who was receiving a dose of 90 mg every 4 weeks, the trough milk sample contained 43 mcg/L of ustekinumab and attained a peak level of 43.1 mcg/L two days after the dose. The milk level dropped to 16.7 mcg/L at 4 days after the dose, then rose again to 26.3 mcg/L at 5 days after the dose. The other two women were receiving a dosage of 90 mg every 8 weeks. One had a trough ustekinumab milk level of 40 mcg/L. After the dose, the milk level gradually rose to a level of 45.1 mcg/L at 6 days after the dose. The third woman, who had not had any doses during pregnancy, had a trough milk value of 3 mcg/L. It rose to a peak of 7.4 mcg/L on day 3 and then plateaued between 5.4 and 6.6 mcg/L on days 4 to 6 after the dose.[11]

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

Effects in Breastfed Infants

One woman receiving ustekinumab for severe psoriasis breastfed her infant. No adverse effects were reported in the infant, although the dosage of ustekinumab and the extent of breastfeeding were not reported.[12]

In a multi-center study of women with inflammatory bowel disease in pregnancy (the PIANO registry), 6 women received a ustekinumab while breastfeeding their infants. Among those who received ustekinumab or another biologic agent while breastfeeding, infant growth, development or infection rate was no different from infants whose mothers received no treatment. An additional 68 women received a biologic agent plus a thiopurine. Infant outcomes were similar in this group.[10]

A woman with treatment-refractory Crohn’s disease was treated during pregnancy with ustekinumab until the third trimester. It was reinitiated 7 weeks postpartum with a loading dose of 390 mg intravenously, then 90 mg every 8 weeks. She breastfed her infant (extent and duration not reported). Follow-up of the infant at 12 months of age was normal.[9]

A woman with severe psoriasis was treated with ustekinumab 45 mg subcutaneously every 12 weeks until pregnancy was confirmed. After delivery ustekinumab was restarted while she was breastfeeding (extent and duration not stated). The infant reportedly had no complications and a normal growth curve.[13]

Three mothers taking ustekinumab for Crohn’s disease breastfed (extent not stated) their infants. Their dosages were 90 mg every 4 weeks in one and 90 mg every 8 weeks in the other two. Infants were followed for 3 to 6 months and no developmental delays or excess infections of hospital admissions were noted.[11]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

(Psoriasis) Adalimumab, Etanercept, Infliximab, Phototherapy, Tretinoin


Smith CH, Yiu ZZN, Bale T, et al. British Association of Dermatologists guidelines for biologic therapy for psoriasis 2020: A rapid update. Br J Dermatol. 2020;183:628–37. [PubMed: 32189327]
Götestam Skorpen C, Hoeltzenbein M, Tincani A, et al. The EULAR points to consider for use of antirheumatic drugs before pregnancy, and during pregnancy and lactation. Ann Rheum Dis. 2016;75:795–810. [PubMed: 26888948]
Amin M, No DJ, Egeberg A, et al. Choosing first-line biologic treatment for moderate-to-severe psoriasis: What does the evidence say? Am J Clin Dermatol. 2018;19:1–13. [PubMed: 29080066]
Mahadevan U, Robinson C, Bernasko N, et al. Inflammatory bowel disease in pregnancy clinical care pathway: A report from the American Gastroenterological Association IBD Parenthood Project Working Group. Gastroenterology. 2019;156:1508–24. [PubMed: 30658060]
Sammaritano LR, Bermas BL, Chakravarty EE, et al. 2020 American College of Rheumatology Guideline for the Management of Reproductive Health in Rheumatic and Musculoskeletal Diseases. Arthritis Rheumatol. 2020;72:529–56. [PubMed: 32090480]
Koenig A, de Albuquerque Diniz EM, Barbosa SF, et al. Immunologic factors in human milk: The effects of gestational age and pasteurization. J Hum Lact. 2005;21:439–43. [PubMed: 16280560]
Adhisivam B, Vishnu Bhat B, Rao K, et al. Effect of Holder pasteurization on macronutrients and immunoglobulin profile of pooled donor human milk. J Matern Fetal Neonatal Med. 2019;32:3016–9. [PubMed: 29587541]
Rodríguez-Camejo C, Puyol A, Fazio L, et al. Antibody profile of colostrum and the effect of processing in human milk banks: Implications in immunoregulatory properties. J Hum Lact. 2018;34:137–47. [PubMed: 28586632]
Klenske E, Osaba L, Nagore D, et al. Drug levels in the maternal serum, cord blood and breast milk of a ustekinumab-treated patient with Crohn's disease. J Crohns Colitis. 2019;13:267–9. [PubMed: 30388211]
Matro R, Martin CF, Wolf D, et al. Exposure concentrations of infants breastfed by women receiving biologic therapies for inflammatory bowel diseases and effects of breastfeeding on infections and development. Gastroenterology. 2018;155:696–704. [PubMed: 29857090]
Bar-Gil Shitrit A, Ben-Horin S, Mishael T, et al. Detection of ustekinumab in breast milk of nursing mothers with Crohn disease. Inflamm Bowel Dis. 2021;27:742–5. [PubMed: 33386732]
Lund T, Thomsen SF. Use of TNF-inhibitors and ustekinumab for psoriasis during pregnancy: A patient series. Dermatol Ther. 2017;30:e12454. [PubMed: 28071837]
Mugheddu C, Atzori L, Lappi A, et al. Biologics exposure during pregnancy and breastfeeding in a psoriasis patient. Dermatol Ther. 2019;32:e12895. [PubMed: 30958637]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Antibodies, Monoclonal

Dermatologic Agents

Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.


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