Risk of Adult-Onset MS Associated with Maternal Pregnancy Outcomes in Study

Individuals born large for their gestational age or exposed to maternal diabetes during pregnancy may have an increased risk for developing multiple sclerosis (MS) in adulthood, according to findings from a population-based cohort study published in JAMA Neurology. In contrast, individuals born small for gestational age showed a lower risk of adult-onset MS compared with those born at an appropriate weight for gestational age. These associations persisted after adjustment for demographic and familial factors, indicating that prenatal growth and metabolic conditions may be linked to long-term MS risk.

This retrospective, population-based cohort study included data from Norwegian national health registries for individuals born between 1967 and 1998. Participants were followed into adulthood and researchers identified MS diagnoses through the Norwegian Patient Registry. Pregnancy and birth characteristics were obtained from the Medical Birth Registry of Norway. Exposure variables included adverse pregnancy outcomes such as preterm birth, small-for-gestational-age (SGA) and large-for-gestational-age (LGA) status, and other perinatal factors. Researchers conducted statistical analyses to adjust for sex, birth year, maternal age, maternal education, and parental history of autoimmune disease.

Key findings from the study include the following:

• Individuals born large for gestational age had a higher risk of developing adult-onset MS compared with those born appropriate for gestational age (adjusted hazard ratio [HR], 1.13; 95% CI, 1.03 to 1.25).
• Small-for-gestational-age birth status was associated with a lower risk of adult-onset MS compared with appropriate-for-gestational-age birth (adjusted HR, 0.88; 95% CI, 0.78 to 0.98).
• Exposure to maternal diabetes during pregnancy was associated with more than a 2-fold increase in risk of adult-onset MS (adjusted HR, 2.15; 95% CI, 1.37 to 3.37)

The authors noted that the cohort was predominantly from Northern Europe, which may limit generalizability, and emphasized that gestational age was based on last menstrual period rather than ultrasonography.

Source: Wolfova K, Engdahl BL, Horn J, et al. Maternal Pregnancy Outcomes and Offspring Risk of Adult-Onset Multiple Sclerosis. JAMA Neurol. Published online January 12, 2026. doi:10.1001/jamaneurol.2025.5255