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.[1] Many infants have been safely breastfed during maternal treatment with ustekinumab. Waiting for at least 2 weeks postpartum to resume therapy suspended during pregnancy may minimize transfer to the infant.[2] Numerous experts and professional guidelines have stated that the drug is a low risk to the nursing infant and acceptable to use during breastfeeding.[3-11]

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.[12]

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.[13]

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.[14]

A pregnant woman with ulcerative colitis received ustekinumab 90 mg 4 times during pregnancy with the last dose at 29 weeks gestation She was also treated with mesalamine 4.8 grams daily during pregnancy and lactation. Postpartum, amlodipine 10 mg daily was begun for hypertension and at 5 days postpartum ampicillin-sulbactam was begun intravenously for suspected endometritis. Subcutaneous ustekinumab was restarted at 48 days postpartum and first detected in milk on day 49 at 1.5 mcg/L. On day 57, the milk concentration was 13.6 mcg/L. Milk concentrations then declined to 10.8, 7.9 and 3.4 mcg/L on days 64, 71 and 78 postpartum, respectively.[15]

Infant Levels. Sixty-nine breastfed infants were born to mothers who received ustekinumab during pregnancy and postpartum. The estimated mean half-life of ustekinumab in infants was 23.2 days (95% CI 21.5 to 24.9 days).[16]

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.[17]

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.[12]

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.[13]

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.[18]

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.[14]

A pregnant woman with ulcerative colitis received ustekinumab 90 mg 4 times during pregnancy with the last dose at 29 weeks gestation. She was also treated with mesalamine 4.8 grams daily during pregnancy and lactation. Postpartum, amlodipine 10 mg daily was begun for hypertension and at 5 days postpartum ampicillin-sulbactam was begun intravenously for suspected endometritis. Subcutaneous ustekinumab was restarted at 7 weeks postpartum. The infant was partially (>50%) breastfed for 3 months. The infant had no adverse drug events at the 1 and 3-month checkups and received routine infant vaccinations with no adverse events.[15]

The DUMBO registry in Spain followed 526 newborns whose mothers had inflammatory bowel disease. During breastfeeding 4% of the mothers were receiving ustekinumab. Of children breastfed at least until month 6 and whose mothers were taking a biologic, 60% received the first and second dose of rotavirus vaccine, and 17% the 3rd dose. Of children breastfed at least until month 12 and whose mothers were taking a biologic, 97% received the first dose of MMR vaccine; and from children breastfed at least until month 15 and whose mothers were under biologics, 84% received the first dose of varicella vaccine. No serious adverse events related to live vaccines were reported.[19]

In a prospective multicenter study, 20 infants were born to mothers taking ustekinumab during pregnancy. Of these, 18 were breastfed for a median of 7 months (range 0.5 to 27 months). Infants were followed for at least 6 months and a median of 18 months. All children had normal growth and normal psychomotor development. All but one child exposed to ustekinumab receive mandatory vaccinations with non-live vaccines without any serious or unexpected adverse events.[20]

A multicenter study in Spain prospectively followed women treated for inflammatory bowel disease with biological agents, mostly anti-TNF agents. Overall, 29% of infants exposed to a biologic agent were also exposed to azathioprine or mercaptopurine and almost all were exposed during both pregnancy and lactation. Twelve infants were exposed to ustekinumab during lactation for a mean duration of 39.5 weeks. No adverse impact of biologics exposure was found on the psychomotor development of infants for up to 1 year of age.[21]

Effects on Lactation and Breastmilk

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

Alternate Drugs to Consider

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

References

1.

Anderson PO. Monoclonal antibodies during breastfeeding. Breastfeed Med 2021;16:591–3. [PubMed: 33956488]

2.

Krysko KM, Dobson R, Alroughani R, et al. Family planning considerations in people with multiple sclerosis. Lancet Neurol 2023;22:350–66. [PubMed: 36931808]

3.

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]

4.

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]

5.

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]

6.

Yeung J, Gooderham MJ, Grewal P, et al. Management of plaque psoriasis with biologic therapies in women of child-bearing potential consensus paper. J Cutan Med Surg 2020;24 (1_Suppl):3S–14S. [PubMed: 32500730]

7.

Russell MD, Dey M, Flint J, et al. British Society for Rheumatology guideline on prescribing drugs in pregnancy and breastfeeding: Immunomodulatory anti-rheumatic drugs and corticosteroids. Rheumatology (Oxford) 2023;62:e48–e88. [PMC free article: PMC10070073] [PubMed: 36318966]

8.

Torres J, Chaparro M, Julsgaard M, et al. European Crohn's and Colitis Guidelines on Sexuality, Fertility, Pregnancy, and Lactation. J Crohns Colitis 2023;17:1–27. [PubMed: 36005814]

9.

Rüegg L, Pluma A, Hamroun S, et al. EULAR recommendations for use of antirheumatic drugs in reproduction, pregnancy, and lactation: 2024 update. Ann Rheum Dis 2025;84:910–26. [PubMed: 40287311]

10.

Laube R, Selinger CP, Seow CH, et al. Australian inflammatory bowel disease consensus statements for preconception, pregnancy and breast feeding. Gut 2023;72:1040–53. [PubMed: 36944479]

11.

Mahadevan U, Seow CH, Barnes EL, et al. Global consensus statement on the management of pregnancy in inflammatory bowel disease. Clin Gastroenterol Hepatol 2025;23 (11S):S1–S60. [PubMed: 40874901]

12.

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]

13.

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]

14.

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]

15.

Saito J, Kaneko K, Kawasaki H, et al. Ustekinumab during pregnancy and lactation: Drug levels in maternal serum, cord blood, breast milk, and infant serum. J Pharm Health Care Sci 2022;8:18. [PMC free article: PMC9248188] [PubMed: 35773736]

16.

Julsgaard M, Wieringa JW, Baunwall SMD, et al. Infant ustekinumab clearance, risk of infection, and development after exposure during pregnancy. Clin Gastroenterol Hepatol 2025;23:134–43. [PubMed: 38278191]

17.

Lund T, Thomsen SF. Use of TNF-inhibitors and ustekinumab for psoriasis during pregnancy: A patient series. Dermatol Ther 2017;30:e12454. [PubMed: 28071837]

18.

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]

19.

Chaparro Sanchez M, García Donday M, Rubio S, et al. Live vaccines in children exposed to biological agents for IBD in utero and/or during breastfeeding: Are they safe? Results from the Dumbo registry of GETECCU. United European Gastroenterol J 2022;10:757–8. doi:10.1002/ueg2.12295 [CrossRef]

20.

Mitrova K, Pipek B, Bortlik M, et al. Safety of ustekinumab and vedolizumab during pregnancy-pregnancy, neonatal, and infant outcome: A prospective multicentre study. J Crohns Colitis 2022;16:1808–15. [PubMed: 35708729]

21.

Palomino L, Rodríguez-Belvís MV, Casanova MJ, et al. Psychomotor development in infants following maternal exposure to biologics: Results from the DUMBO registry. Clin Gastroenterol Hepatol 2025 [PubMed: 40518059]

Substance Name

Ustekinumab

CAS Registry Number

815610-63-0

Drug Class

Breast Feeding

Lactation

Milk, Human

Antibodies, Monoclonal

Dermatologic Agents