Pregnancy outcomes in multiple sclerosis following subcutaneous interferon beta-1a therapy

Background: Women with multiple sclerosis (MS) are advised to discontinue interferon-beta therapy before trying to conceive. Unplanned pregnancies occur and risks related to exposure remain unclear.Methods: To determine pregnancy outcomes following interferon-beta therapy, we examined pregnancies from a global drug safety database containing individual case safety reports received in the post-marketing setting and safety data from clinical trials of subcutaneous interferon beta-1a in MS.Results: One thousand and twenty-two cases of exposure to subcutaneous interferon beta-1a during pregnancy were retrieved; 679 had a documented outcome. In cases for which exposure duration was available (n = 231), mean time of foetal exposure to subcutaneous interferon beta-1a before treatment discontinuation was 28 days; most pregnancies (199/231; 86.1%) were exposed for ≤45 days. To avoid bias, only outcomes for prospective data (n = 425) in pregnancies exposed to interferon beta-1a in utero were analysed further. Of th...