Methods
Study design
The EUROmediCAT database only holds data for babies with CA among live births (LB), fetal deaths (FD) from 20 weeks gestational age and terminations of pregnancy following prenatal diagnosis of fetal anomaly (TOPFA) at any gestational age. It does not include any data on babies without CA that may be used as non-malformed controls. We therefore performed a case-malformed control study. Cases were babies with CA associated in the epidemiologic literature with any antibiotic exposure. Controls were babies with other CA or genetic conditions. To avoid confusion, throughout this paper the term ‘registration’ refers to babies/fetuses with CA including both cases and controls