Prevalence of adverse pregnancy outcomes after exposure to interferon beta prior to or during pregnancy in women with MS: Stratification by maternal and newborn characteristics in a register-based cohort study in Finland and Sweden

BackgroundPrevious studies reported no increase in the prevalence of adverse pregnancy outcomes after exposure to interferon-beta (IFN-beta). However, study has investigated if these IFN-beta is modified by maternal and newborn characteristics. Our objective was describe stratified among women with multiple sclerosis (MS) exposed only or unexposed any MS disease modifying drugs (MSDMDs).MethodsThis population-based cohort using Finnish (1996-2014) Swedish (2005-2014) register data included pregnancies 6 months before during (n=718) MSDMDs (n=1397). The outcome prevalences were described characteristics, 95% confidence intervals (CIs). Confounder-adjusted analyses performed results indicated effect specific strata.ResultsThe analysis that serious (anomaly stillbirth) other similar unexposed, statistically significant difference. Among treated for >5 years, occurred 4.3% (95%CI: 1.9-8.3%) 2.7% 1.2-5.0%) pregnancies. confounder adjusted did not support hypothesis treatment duration would modify risk pregnancy.ConclusionThe increased exposure, when unstratified same population.