The drug fingolimod (Gilenya) is sometimes prescribed for people with relapsing forms of multiple sclerosis (MS) to reduce flare-ups and ease symptoms. However, it may not be safe to take if you're pregnant. Based on animal studies, the U.S. Food and Drug Administration (FDA) has given fingolimod a pregnancy category C rating, indicating that it could harm your unborn baby.

As of yet, there are no adequate, well-controlled studies of fingolimod in pregnant women. A pregnancy registry has been established to track outcomes of fingolimod use during pregnancy, but the reported number of pregnancies is too few to form firm conclusions about using the drug during pregnancy. However, preliminary data indicates a possible risk of fingolimod-related developmental problems.

Fingolimod may take approximately two months to be completely eliminated from your body. Because of the potential risk to the baby while the drug is still in your system, the prescribing information advises women who may become pregnant to use effective contraception to avoid pregnancy during and for two months after stopping fingolimod treatment.

Fingolimod should be discontinued immediately if a woman gets pregnant while on the medication. These women should also be monitored with early ultrasound for major fetal malformations and maternal rebound disease activity.