Interferon-beta exposure during first trimester is safe in women with multiple sclerosis-A prospective cohort study from the German Multiple Sclerosis and Pregnancy Registry.

BACKGROUND Available data suggest that pregnancy exposure to interferon-beta might result in lower mean birth weight and preterm birth. OBJECTIVE To determine the effect of interferon-beta exposure during pregnancy on pregnancy outcomes in multiple sclerosis patients. METHODS We compared the pregnancy outcomes of women exposed to interferon-beta with pregnancies unexposed to disease-modifying therapies. Women were enrolled into the German Multiple Sclerosis and Pregnancy Registry. A standardized questionnaire was administered during pregnancy and postpartum. Detailed information on course of multiple sclerosis and pregnancy, concomitant medications, delivery, and outcome of pregnancy was obtained. RESULTS We collected data on 251 pregnancies exposed to interferon-beta and 194 unexposed to disease-modifying therapies. In all, 246 (98.01%) women discontinued interferon-beta treatment during first trimester. No differences regarding mean birth weight (exposed: 3272.28 ± 563.61 g; unexposed: 3267.46 ± 609.81 g), mean birth length (exposed: 50.73 ± 3.30 cm; unexposed: 50.88 ± 3.45 cm), preterm birth (p = 0.187), spontaneous abortion (p = 0.304), and congenital anomalies (p = 0.197) were observed between the two groups. CONCLUSIONS Interferon-beta exposure during early pregnancy does not influence the mean birth weight, risk of preterm birth, or other adverse pregnancy outcomes. Our study provides further reassurance that interferon-beta treatment can be safely continued up until women become pregnant.