Anorexia nervosa has potential to influence the development and function of the gastrointestinal system. We assessed the association between maternal anorexia nervosa and risk of gastrointestinal morbidity in offspring.

We analyzed a longitudinal cohort of 1,269,370 children born in Quebec, Canada, between 2006 and 2022. The exposure was maternal anorexia nervosa. The outcome was hospitalization for pediatric gastrointestinal disorders, including hypertrophic pyloric stenosis, inflammatory bowel disease, and other digestive morbidity. Follow-up ranged from 1 to 17 years. We used adjusted Cox regression models to obtain hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between maternal anorexia nervosa and pediatric gastrointestinal disorders.

A total of 2,447 children (0.2%) had a mother with anorexia nervosa. By age 17 years, the cumulative incidence of gastrointestinal disorders was higher among children whose mothers had anorexia nervosa than other children (165.7 vs. 129.4 per 1,000). Compared with no anorexia, maternal anorexia nervosa was associated with a greater risk of any childhood gastrointestinal disorder (HR: 1.42, 95% CI: 1.26–1.61), particularly hypertrophic pyloric stenosis (HR: 2.51, 95% CI: 1.35–4.66), inflammatory bowel disease (HR: 2.46, 95% CI: 1.67–3.64), and rectal hemorrhage (HR: 3.46, 95% CI: 1.97–6.09). Children whose mothers developed anorexia nervosa after age 20 years or were hospitalized more than once for anorexia had the greatest risk of gastrointestinal morbidity. The associations were not explained by digestive birth defects.

Maternal anorexia nervosa is associated with pediatric gastrointestinal disorders that could potentially be mitigated with psychosocial support, nutritional rehabilitation, and breastfeeding.