Last update June 12, 2020


Likely Compatibility

Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.

Soluble fusion protein used for treatment of Rheumatoid Arthritis and other autoimmune diseases.
Abatacept is a biological disease-modifying antirheumatic drug (DMARD).
Weekly administration subcutaneously.

Its very high molecular weight probably explain the negligible excretion observed in milk (Saito 2019). No health or immunization problems have been observed in an infant breastfed by a mother treated with abatacept (Saito 2019).

Its nil oral bioavailability would make it difficult its passage to the infant’s plasma through breast milk except in premature babies and in the immediate neonatal period during which there may be greater intestinal permeability.

Several medical societies, experts and expert consensus, consider the use of this medication to be compatible or very probably compatible during breastfeeding if no other options are available (Sammaritano 2020, Hale 2019, Götestam 2016).


  • Etanercept (Safe substance and/or breastfeeding is the best option.)
  • Infliximab (Safe substance and/or breastfeeding is the best option.)

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Abatacept is also known as

Abatacept in other languages or writings:


Abatacept belongs to this group or family:


Main tradenames from several countries containing Abatacept in its composition:


Variable Value Unit
Oral Bioavail. 0 %
Molecular weight 92.000 daltons
VD 0.02 - 0.13 l/Kg
192 - 600 hours


  1. Hale TW. Medications & Mothers' Milk. 1991- . Springer Publishing Company. Available from Consulted on April 10, 2024 Full text (link to original source)
  2. Sammaritano LR, Bermas BL, Chakravarty EE, Chambers C, Clowse MEB, Lockshin MD, Marder W, Guyatt G, Branch DW, Buyon J, Christopher-Stine L, Crow-Hercher R, Cush J, Druzin M, Kavanaugh A, Laskin CA, Plante L, Salmon J, Simard J, Somers EC, Steen V, Tedeschi SK, et al. 2020 American College of Rheumatology Guideline for the Management of Reproductive Health in Rheumatic and Musculoskeletal Diseases. Arthritis Rheumatol. 2020 Apr;72(4):529-556. Abstract Full text (link to original source)
  3. Saito J, Yakuwa N, Takai C, Kaneko K, Goto M, Nakajima K, Yamatani A, Murashima A. Abatacept concentrations in maternal serum and breast milk during breastfeeding and an infant safety assessment: a case study. Rheumatology (Oxford). 2019 Sep 1;58(9):1692-1694. Abstract
  4. Götestam Skorpen C, Hoeltzenbein M, Tincani A, Fischer-Betz R, Elefant E, Chambers C, da Silva J, Nelson-Piercy C, Cetin I, Costedoat-Chalumeau N, Dolhain R, Förger F, Khamashta M, Ruiz-Irastorza G, Zink A, Vencovsky J, Cutolo M, Caeyers N, Zumbühl C, Østensen M. The EULAR points to consider for use of antirheumatic drugs before pregnancy, and during pregnancy and lactation. Ann Rheum Dis. 2016 May;75(5):795-810. Abstract Full text (link to original source) Full text (in our servers)
  5. Witzel SJ. Lactation and the use of biologic immunosuppressive medications. Breastfeed Med. 2014 Dec;9(10):543-6. Abstract Full text (link to original source) Full text (in our servers)
  6. AEMPS-BMS. Abatacept Ficha técnica. 2012 Full text (in our servers)
  7. BMS. Abatacept. Drug Summary. 2009 Full text (in our servers)

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