STOCKHOLM – Most neurologists are overly conservative when it comes to advising women with multiple sclerosis (MS) about breastfeeding, discouraging this broadly beneficial practice in favor of early resumption of treatment post pregnancy, Kerstin Hellwig, MD, said at the annual congress of the European Committee for Treatment and Research in Multiple Sclerosis.
Bruce Jancin/MDedge News
Dr. Kerstin Hellwig
“We should change our behavior, and I predict we will change it so that more women are breastfeeding while under MS medication within the next couple years. ,” said Dr. Hellwig, senior consultant and MS specialist in the department of neurology at St. Josef Hospital/Ruhr University in Bochum, Germany.
She was a coauthor of a groundbreaking 2012 meta-analysis that concluded that breastfeeding by MS patients is not harmful (J Neurol. 2012 Oct;259[10]:2246-8), a finding since confirmed in multiple additional studies.
“Women with MS who want to breastfeed should be supported in doing so,” Dr. Hellwig said.
In this regard, many neurologists are out of step with their colleagues in rheumatology and gastroenterology, who commonly endorse breastfeeding by their patients while on monoclonal antibodies for other autoimmune diseases, according to Dr. Hellwig.
It is important to recognize that most women of reproductive age with MS have milder forms of the disease, she said. They can safely breastfeed without being on any MS medications at all for the duration.
For women who want to breastfeed and have more-active disease where early treatment resumption is warranted, the key is to select a breastfeeding-compatible medication. The main determinant of whether a drug will enter the mother’s breast milk is the size of the drug molecule, with large molecules being unlikely to make their way into breast milk in anything approaching clinically meaningful amounts. The injectable first-line disease-modifying drugs are good options: For example, interferon-beta is a very large molecule which has been detected in breast milk at 0.0006% of the relative infant dose. That’s reassuring, Dr. Hellwig said, since anything less than a relative infant dose of 10% is generally considered to be safe for a baby. And while glatiramer acetate, another injectable, has not been tested, it is metabolized so rapidly that it is unlikely to be detectable in breast milk, according to Dr. Hellwig.
Monoclonal antibodies are also compatible with breastfeeding. Rituximab has been detected in breast milk at 1/240th of the maternal serum level, and natalizumab at less than 1/200th. These are large molecules with a low likelihood of infant absorption, since they are probably destroyed in the child’s gastrointestinal tract. Ocrelizumab has not been studied in breast milk, but it is an IgG1 monoclonal antibody, as is rituximab, and so should likewise pose “exceedingly low risk,” Dr. Hellwig said.
At last year’s ECTRIMS conference, she presented reassuring 1-year follow-up data on a cohort of infants breastfed by mothers with MS while on interferon-beta. “We do not see any growth disturbances, any severe infections, hospitalizations, excess antibiotic use, or postponed reaching of developmental milestones in babies being breastfed under the injectables,” she said.
Dr. Hellwig has served on scientific advisory board for Bayer, Biogen, Genzyme Sanofi, Teva, Roche, Novartis, and Merck. She has received speaker honoraria and research support from Bayer, Biogen, Merck, Novartis, SanofiGenzyme, and Teva, and has received support for congress participation from Bayer, Biogen, Genzyme, Teva, Roche, and Merck.