Medications used to treat multiple sclerosis (MS) during breastfeeding present a complex challenge because there is limited definitive research on their safety for nursing infants. Many MS drugs have not been adequately studied in breastfeeding women, so healthcare providers and mothers must carefully weigh the potential benefits of treatment against possible risks to the baby.
Multiple sclerosis is a chronic neurological condition that often requires ongoing treatment with disease-modifying therapies (DMTs) to reduce relapses and slow disease progression. These medications include a variety of types such as injectable therapies, oral drugs, and monoclonal antibodies. When a woman with MS becomes a mother and chooses to breastfeed, the question arises: are these medications safe to continue during lactation?
The main difficulty in answering this question is the lack of comprehensive studies on how much of these drugs pass into breast milk and what effects they might have on an infant. For many MS medications, the data are either very limited or completely absent. This is partly because pregnant and breastfeeding women have historically been excluded from clinical trials, leaving a significant knowledge gap.
Some newer studies and registries are beginning to collect data on the presence of MS drugs in breast milk. For example, ongoing research is examining the concentration of monoclonal antibodies like ofatumumab, ublituximab, ocrelizumab, and others in breast milk to better understand exposure levels for nursing infants. These studies aim to provide clearer guidance in the future, but currently, the evidence remains preliminary.
For oral MS medications such as teriflunomide and ponesimod, official prescribing information often states that there are no adequate studies to determine infant risk during breastfeeding. These drugs may have potential risks because they are systemic and can be present in bodily fluids, but the exact impact on infants is unknown. Therefore, doctors usually recommend weighing the benefits of continuing treatment against the unknown risks to the baby, sometimes suggesting alternative therapies or temporary discontinuation during breastfeeding.
Injectable therapies like interferon beta and glatiramer acetate have been used more extensively and are generally considered relatively safer during breastfeeding. Interferon beta, for example, is thought to have minimal transfer into breast milk and low oral bioavailability in infants, which reduces the likelihood of adverse effects. Glatiramer acetate is also often regarded as compatible with breastfeeding, though definitive long-term safety data are still limited.
Monoclonal antibodies, which are large protein molecules, tend to have limited passage into breast milk due to their size, and even if present, they are likely broken down in the infant’s digestive system. However, because these drugs affect the immune system, there is caution about their use during breastfeeding until more data are available.
The decision to use MS medications while breastfeeding is highly individualized. It involves considering the severity of the mother’s disease, the specific medication’s known or suspected safety profile, and the mother’s preference regarding breastfeeding. In some cases, the risk of MS relapse if treatment is stopped may outweigh the potential but uncertain risks to the infant.
Healthcare providers often recommend close monitoring of both mother and baby if MS medications are continued during breastfeeding. They may also suggest collecting breast milk samples for analysis or enrolling mothers in pregnancy and lactation registries that track outcomes to improve future knowledge.
It is important to note that breastfeeding itself offers many benefits to both mother and child, including immune protection and bonding, which can be especially valuable for women managing chronic illnesses like MS. Therefore, decisions about medication use during breastfeeding aim to balance maintaining maternal health and supporting safe breastfeeding practices.
In summary, while some MS medications like interferon beta and glatiramer acetate are generally considered safer during breastfeeding, many others lack sufficient safety data. Ongoing research is working to fill these gaps, but until more is known, treatment decisions during breastfeeding require careful discussion between a woman and her healthcare team to tailor the approach to her unique situation.
