Purpose of Review:: This article reviews the current understanding of the interactions between multiple sclerosis (MS) and pregnancy, and implications for reproductive counseling. This is a key topic in MS because the typical patient is a young woman of childbearing age.
Recent Findings:: It has been known for some time that MS disease activity markedly reduces during the last trimester of pregnancy, then markedly increases in the 3 months postpartum before returning to the prepregnancy baseline. High relapse rate or disability before pregnancy, as well as relapse during pregnancy, have been associated with increased risk for postpartum attacks. Recent data continue to support the conclusion that long-term disease progression is not worsened (and may actually be lessened) with pregnancy in patients with relapsing MS; the data are not so clear for those with progressive MS. Among the MS disease-modifying therapies, the only one that requires contraception use by men is the new oral agent teriflunomide, because the drug is present in semen. It is reassuring that, to date, no human teratogenic effects have been documented for any of the MS disease-modifying therapies.
Summary:: Pregnancy has a profound effect on MS disease activity. Identification of the responsible mechanisms for this effect should lead to new disease insights and therapeutic strategies.