Increased Risk Tied to Mothers Who Developed RA Before Delivery, Not After
A prospective population-based cohort study from Sweden found an increased risk of autism spectrum disorder (ASD) in offspring whose mothers developed rheumatoid arthritis (RA) before pregnancy or delivery. This effect was even more pronounced for mothers with seronegative RA, where rheumatoid factor or antibodies are not circulating in the blood. The authors also discovered a higher risk of ASD for post-term births (a pregnancy lasting more than 42 weeks) and offspring of underweight or overweight mothers. This research found no association between maternal RA and offspring ASD when RA was diagnosed after delivery, for paternal RA, or maternal-sister RA. Previous research has suggested that the association between maternal RA and ASD is due to exposure to auto-antibodies and inflammatory mediators/cytokines in the womb, which could alter fetal brain development. The authors of this study challenged this hypothesis by using a control group of women with arthralgia (joint pain due to injury, infection, or overuse). Interestingly, they found a similar ASD risk in offspring for both conditions. The authors concluded from this finding that other risk pathways than inflammation/autoimmunity could underlie the RA-ASD association. They propose that the association may be driven by ASD risk factors shared by women with joint pain or that RA and arthralgia could have different causes independently associated with ASD risk.
