Multiple Sclerosis, often referred to as MS, is an unpredictable disease that affects the central nervous system. The disease can debut at any age, but most often manifests between the ages of 20 and 40 and women are more at risk. Certain forms of MS respond well to a drug called dimethyl fumarate. Because we don’t know enough about how this drug transfers to breastmilk, new mothers who are on this medication often face difficult decisions about breastfeeding. A recent case report published in Frontiers in Public Health shares findings that help fill this knowledge gap – towards a future where women can make informed decisions.
MS disrupts the communication within the brain, and between the brain and body. Dimethyl fumarate can help protect the nerves and prevent the disease from progressing. And although breastfeeding has benefits for both mother and child, to prevent the infant from unnecessary risk, dimethyl fumarate is often advised against during breastfeeding by healthcare professionals when there is not enough evidence that confirms a drug is safe for them too.
“With this case report, we are completing part of the puzzle. From what we can tell, so far, a small amount of the drug transfers from the mother’s blood into her breastmilk. This indicates that the infant exposure is also low. But to complete the puzzle, we need more evidence. This is the goal of ConcePTION, taking a comprehensive approach that integrates data from multiple sources and employs robust methodologies to assess the safety of medicines for pregnant and breastfeeding women,” says Martje Van Neste, MD & PhD student at KU Leuven and one of the authors of the recent Frontiers in Public Health publication.
One previous case series has reported low infant exposure of dimethyl fumarate in breastfeeding. Both case reports provide estimations, as none of the infants ingested the breastmilk. The current case report covers a patient who took dimethyl fumarate (120 mg, twice per day) and expressed milk, when the baby was already weaned. Based on the amount of the drug that was in the mother’s milk, it was possible for the researchers to calculate an estimation of how much of the drug in the mother’s milk would have transferred into the blood stream of the baby.
Compared with the other available cases, three women in total, there is a high variability of medication levels in breastmilk. This means how much of the drug is transferred into the breastmilk differs between individuals, and even between samples from the same mother. According to the authors, it is important to note that because no infants actually ingested the breastmilk, it is not possible to say for certain how much of the drug is absorbed and what the effects of exposure would be.
“Studying medicine safety in breastfeeding is complicated. Researchers need more data but at the same time we want to encourage caution to protect these children. Making sure it is possible to collect and analyse breastmilk samples and data from real-world cases is key to close this knowledge gap. It is a slow process, and I’m sure it’s frustrating to many women who face these decisions between continuing treatment and breastfeeding that we cannot yet offer a straight answer. But at least we can tell them that there are networks of researchers working to fill these knowledge gaps,” Martje Van Neste concludes.
Want to read the paper? Van Neste, M., Nauwelaerts, N., Ceulemans, M., Cuppers B., Annaert, P., Smits, A. & Allegaert, K., Very low monomethyl fumarate exposure via human milk: a case report—a contribution from the ConcePTION project, Front. Public Health, Volume 12, 02 July 2024, DOI: 10.3389/fpubh.2024.1393752
Want to take a look at the study protocol? Van Neste, M., Nauwelaerts, N., Ceulemans, M., Van Calsteren, K., Eerdekens, A., Annaert, P., Allegaert, K., & Smits, A. Determining the exposure of maternal medicines through breastfeeding: the UmbrelLACT study protocol—a contribution from the ConcePTION project, BMJ Paediatrics Open 2024;8:e002385. DOI: 10.1136/bmjpo-2023-002385
By Anna Holm Bodin
