43 msfocusmagazine.org temporarilyright afterdelivery. Some evidence suggests that pregnancy may have favorable long-term effects on MS, such as slowing progression of disability. Disease-modifying therapy and pregnancy There are more than a dozen different DMTs for the treatment of MS and each has different implications for pregnancy. According to the FDA,DMTsshouldnotbetakenwhileattempting to conceive, pregnant, or breastfeeding. For a patient with stable and well-controlled MS, we typically recommend discontinuing DMT and waiting for the medication to be eliminated from the body prior to attempting conception (Table 1). For women with more active MS, we may consider periodic treatment with steroids toreducetheriskofrelapseinthepre-conception stage.Someclinicalcircumstancesmaywarrant ongoing treatment while pregnant, but this decision should be made only after a careful explorationoftherisksforharmtothefetusand motherwith orwithout DMTduring pregnancy. Disease-modifyingTherapy Last dose prior to conception Effects on the embryo Breastfeeding Notes Interferons 2 months No increased risk of Probably safe miscarriage or birth defect in humans, but embryolethal in animals Glatiramer acetate 1 to 2 months (some No increased risk of Probably safe neurologists will continue miscarriage or birth defect through pregnancy) in humans or animals Dimethyl fumarate A few days or weeks No increased risk of Avoid miscarriage or birth defects in humans but embryolethal in animals Fingolimod 2 months Reports of birth defects Avoid RiskofreboundMSactivitywhen (no pattern), embryolethal stopping without management and teratogenic in animals strategy Teriflunomide Both men and women taking No increased risk of Avoid Contraindicated in pregnancy teriflunomide should undergo miscarriage or birth defects elimination procedure prior to in humans, but embryolethal conception in animals Natalizumab 2 months Possible increased risk of Avoid Risk of rebound MS activity miscarriage in humans; when stopping without embryolethal in animals management strategy Ocrelizumab/Rituzimab* 9-12 months No increased risk of Avoid Risk of B-cell depletion and miscarriage or birth defects other blood issues in the in humans or animals newborn Alemtuzumab 4 months No increased risk of Avoid Thyroid monitoring is miscarriage or birth within necessary throughout defects in humans, four months pregnancy but embryolethal in of last dose animals Table 1. Commonly used disease modifying therapeutics in MS. *Rituximab is not FDA approved for the treatment of MS.