In Utero Exposure to Disease-Modifying MS Drugs May Harm Offspring



NEW ORLEANS—Exposure to disease-modifying multiple sclerosis (MS) drugs could adversely affect the fetus, according to a study that was presented at the 64th Annual Meeting of the American Academy of Neurology.

In addition, women with MS who took interferon beta before conception or during pregnancy had an increased risk of preterm birth (ie, at a gestational age of less than 37 weeks). Babies born to these women also had an increased risk of lower birth weight and shorter birth length. Both measures were still within the normal range for the general population, however.

In utero exposure to mitoxantrone, in particular, could harm offspring. Although no controlled human studies of mitoxantrone’s effects on unborn children have been performed to date, animal studies and human case reports suggest a risk of fetal harm after the mother or father is exposed to the drug, reported Ellen Lu, a PhD student at the University of British Columbia in Vancouver.

A Retrospective Evaluation of the Safety of MS Drugs for Fetuses
Ms. Lu and her colleagues reviewed the literature published before February 2012 to assess the effects of periconceptional or in utero exposure to interferon beta, glatiramer acetate, natalizumab, mitoxantrone, or fingolimod on perinatal and developmental outcomes in the children of patients with MS. The researchers evaluated the level and quality of evidence in the studies by examining their study designs and methods of data collection.

A total of 15 studies identified 761 pregnancies exposed to interferon beta, 97 exposed to glatiramer acetate, and 35 exposed to natalizumab. The quality of the studies ranged from poor to good. No study was considered excellent, and small sample sizes limited most of the studies. The researchers assigned each drug a Class of Recommendation regarding its use during pregnancy according to international guidelines.

Should MS Drugs Be Discontinued Before Conception?
The researchers concluded that mitoxantrone was harmful to the fetus during pregnancy, and that interferon beta may be harmful. Further studies of glatiramer acetate, natalizumab, and fingolimod are necessary because limited data were available for these drugs. In addition, no peer-reviewed studies on fingolimod have been published because the drug entered the market in 2011.

“Women with MS should be advised to discontinue disease-modifying drugs before conceiving,” said the researchers. Women also should consider discontinuing disease-modifying drugs if they are unintentionally exposed to them during pregnancy, they added.

Future research should explore birth outcomes following periconceptional exposure to disease-modifying drugs in fathers with MS and long-term development in offspring exposed to disease-modifying drugs, they concluded.

—Erik Greb

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