Dataset exclusions
We applied the following exclusions to our original dataset:
1) the South East (SE) Ireland registry was excluded from the dataset
because there were no registrations with a first trimester antibiotic
exposure; Reunion-France and Ukraine registries were excluded because
they recorded no macrolide exposure;
2) TOPFAs were excluded from the Emilia Romagna registry as information
on medications is only available for LB and stillbirths;
3) registrations with isolated hip dislocation/dysplasia were excluded
based on the known association with birthweight and potential for
confounding;
4) registrations with mothers with epilepsy or pregestational diabetes,
or mothers who took anti-epileptics or hypoglycaemic agents were
excluded due to the known association with CA;
5) registrations which had antibiotic exposures of unknown timing or
missing description were excluded (90% of these were from three
registries: Saxony-Anhalt-Germany, Wielkopolska-Poland and Poland
excluding Wielkopolska). These exclusions reduced the dataset from
170,062 to 145,936 registrations as shown in Figure 1.