Silvia Segovia Chacón

1 Introduction Most pregnant women use prescription medications and studies from both Europe and North America have demonstrated increases over time [1-5]. In Sweden, the last national overview of medication use during pregnancy was reported in 2011 [6]. Since then, both maternal characteristics and healthcare practices have evolved. There is therefore a need to update our understanding of medication use during pregnancy and postpartum.

Study question What is the proportion of children with detected major congenital malformations (MCM) at birth, 90 days, 1, 2, and 3 years after birth in Sweden? What is already known In observational medication pregnancy safety studies, children are often followed from birth to 1 year of age. However, some MCM may take longer to diagnose. What this study adds Detection of MCM varied by subgroup (e.g., eye and genital MCM require longer follow-up compared to abdominal wall and digestive system MCM).