Women with MS who choose to go on interferon beta drugs are advised to stop treatment if they decide to try to become pregnant. This advice is based on data from animal studies that suggest these drugs may increase the risk of miscarriage. However, since animal studies are imperfect substitutes for human experience, a group of doctors decided to pore through pregnancy data collected during eight IFN-b trials to determine whether being on the drug did have an impact on pregnancy outcome. They found that IFN-b did appear to slightly increase the risk of miscarriage but not to a significant degree. "Reviewing the data from each of the trials, the team found 31 women who conceived while on the drug or within two weeks of ending treatment, and who chose not to terminate their pregnancy. Of these, 22 gave birth to live infants (although one was born prematurely and another had a birth defect). The other 9 miscarried or experienced fetal death (loss of pregnancy after 20 weeks). This on-treatment pregnancy loss rate is higher than the average estimated rate in the general population, but not significantly so. Also identified in the study data were 22 women who had been on IFN-b but stopped two or more weeks prior to becoming pregnant. Each of these women delivered live infants, although one was born prematurely and another had a congenital abnormality.
Overall, these data indicate that IFN-beta treatment does not dramatically increase the rate of lost pregnancies and that the majority of women who conceive while on treatment go on to deliver healthy babies. However, because of the slightly increased risk of pregnancy loss, women who are planning to become pregnant are still advised to end treatment at least two weeks before conceiving."...Click to read ...Entrez PubMed