Maternal autoimmune disease is not associated with cancer in the offspring

Aim Autoimmune disease and its medication are associated with increased cancer risk in adults, but it is unknown whether maternal autoimmune disease and/or medication use in pregnancy are associated with increased cancer risk in offspring. Methods In this case-control study we identified all patients under 20 years of age with their first cancer diagnosis in 1996-2014 from the Finnish Cancer Registry (n=2,029) and 1:5 population- based controls (n=10,103) from the Medical Birth Register. We obtained information on maternal autoimmune disease and its medication from the relevant Finnish registries and used conditional logistic regression to analyse the risk of offspring cancer after maternal autoimmune disease exposure. Results The odds ratio (OR) for cancer in offspring following maternal autoimmune exposure was 0.76 (95% confidence interval (CI) 0.47-1.23). Individual ORs for inflammatory bowel, connective tissue diseases were 1.08 (95% CI 0.56-2.01), 0.50 (95% CI 0.23-1.08), respectively. The OR for maternal autoimmune medication was 0.95 (95% CI 0.80-1.14) overall, and similar by drug subtype. There was an increased risk with medication in late pregnancy but the ORs were unstable owing to small numbers. Conclusion Our study does not support an increased cancer risk among offspring of women with autoimmune disease or its medication during pregnancy.