The safety of paternal and maternal use of 5‐aminosalicylic acid during conception and pregnancy: a nationwide cohort study

BACKGROUND: Data on the safety of paternal use of 5‐aminosalicylic acid (5‐ASA) prior to conception are lacking, and the safety of maternal use of 5‐ASA during pregnancy has not been examined in nationwide data. AIMS: To examine offspring outcomes after paternal pre‐conception use of 5‐ASA, and after maternal use during pregnancy METHODS: This nationwide cohort study was based on Danish health registries. The study population included live born singletons of patients with ulcerative colitis (UC) or Crohn's disease (CD). Paternal exposure included 2168 children fathered by men treated with 5‐ASA, and 7732 unexposed. Maternal exposure included 3618 children exposed in utero to 5‐ASA, and 7128 unexposed. The outcomes were pre‐term birth, small for gestational age (SGA), low Apgar score and major congenital abnormalities (CAs) according to EUROCAT guidelines. RESULTS: The vast majority of fathers and mothers used mesalazine. In children fathered by men with UC using 5‐ASA, we found no increased risk of pre‐term birth, SGA or low Apgar score. The hazard ratio (HR) of CAs was 1.30 (95% CI 0.92–1.85). In children of fathers with CD, the odds ratio (OR) of SGA was 1.52 (95% CI 0.65–3.55). After maternal 5‐ASA exposure, the OR of SGA in children of women with UC was 1.46 (95% CI: 0.93–2.30); for CAs in children of women with CD, HR was 1.44 (95% CI 0.84–2.47). CONCLUSIONS: Paternal and maternal use of 5‐ASA was safe across offspring outcomes; none of the findings reached statistical significance. The safety of 5‐ASA formulations that are used infrequently cannot be settled here.