Rebif and Pregnancy
Rebif (interferon beta-1a) may not be safe for pregnant women. In animal studies on Rebif and pregnancy, the drug increased the risk of miscarriages when it was given to pregnant monkeys in high doses. Small studies in pregnant women also show that the drug may cause miscarriages in humans. Due to these risks, contact your healthcare provider if you are taking Rebif and pregnancy occurs.
Rebif® (interferon beta-1a) is a prescription injection used to treat multiple sclerosis (known commonly as MS). Studies of Rebif in pregnant animals suggest that the drug may increase the risk of miscarriages when used during pregnancy.
The U.S. Food and Drug Administration (FDA) uses a category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category C is given to medicines that have not been studied in pregnant humans but that do appear to cause harm to the fetus in animal studies. Also, medicines that have not been studied in any pregnant women or animals are automatically given a pregnancy Category C rating.
When given to pregnant monkeys at doses equivalent to twice the human dose, Rebif increased the risk of miscarriages. It did not appear to increase the risk of birth defects. The drug has only been studied in a few pregnant women, too few to make any conclusions. In these studies, a total of seven women were pregnant. Two of these women experienced miscarriages while taking Rebif.
However, it is important to note that animals do not always respond to medicines the same way that humans do. Therefore, a pregnancy Category C medicine may be given to a pregnant woman if her healthcare provider believes that the benefits to the woman outweigh any possible risks to the unborn child.