A Norwegian cohort study showed that prenatal and perinatal factors are associated with the development of multiple sclerosis (MS) in offspring. Prenatal exposure to maternal diabetes was associated with twice the risk of developing MS in adulthood (HR 2). According to the study, the risk of MS can start before birth. The study analyzed the associations between factors in pregnancy and the perinatal period and the later incidence of MS. The main finding confirms the influence of maternal diabetes on the increased risk in children in adulthood.