Some studies have suggested that pregnant women are more susceptible to microbial infections, including virus infections, but alternatively can result in a reduction in autoimmune diseases, such as multiple sclerosis. Type I Interferons (IFN-I) play a central role in the regulation of the immune response to viral infections and autoimmune diseases. However, little is known about the consequences of pregnancy on the IFN-I pathway. A better understanding of the interplay between pregnancy, sex hormones, and IFN-I will be important to therapeutically intervene in case of disease during pregnancy.