Adverse Birth and Child Outcomes in Children Fathered by Men Treated with Antidiabetics Prior to Conception: A Nationwide Cohort Study

Background: The safety of fathers’ use of antidiabetic drugs in terms of child outcomes is an important clinical question. We aimed to assess the risk of adverse birth and early childhood outcomes after fathers’ use of antidiabetics prior to conception. Methods: A nationwide cohort study based on Danish health registries. The study comprised all live born singleton children in Denmark (1997 through 2018). Children were categorized according to fathers’ filled prescriptions for antidiabetic drugs three months prior to conception. Exposed cohorts: children born after paternal use of insulin or non-insulin anti-hyperglycemic agents. The unexposed constituted children born by fathers not treated with antidiabetics prior to conception. We examined adverse birth outcomes (preterm birth, small for gestational age (SGA)), and adverse childhood outcomes in the first year of life (major congenital malformations (MCMs), and infections diagnosed at a hospital). Results: A total of 1,318,684 children were included. In all, 5527 children were born after paternal use of insulin, 2121 after use of non-insulin anti-hyperglycemic agents, and 1,311,036 were unexposed. After fathers’ use of insulin we did not find increased risk of adverse outcomes. After fathers’ use of metformin, the adjusted OR of MCMs was 1.40 (95% CI 1.11–1.76). After fathers’ use of sulfonylureas, the adjusted OR of SGA was 1.80 (95% CI 1.11–2.93), and for child gastrointestinal infections the adjusted HR was 1.76 (95% CI 1.04–2.99). Conclusions: Fathers’ use of insulin was reassuring. Metformin and sulfonylureas were associated with selected adverse outcomes. Our findings suggest an additional 14 MCMs per 1000 fathers exposed to metformin prior to conception. As there is no meaningful supporting biological rationale, these findings should be confirmed in a different population prior to clinical consequences being drawn.