OBJECTIVES: The aim of this study was to describe the epidemiology of Ebstein's 
anomaly in Europe and its association with maternal health and medication 
exposure during pregnancy.
DESIGN: We carried out a descriptive epidemiological analysis of 
population-based data.
SETTING: We included data from 15 European Surveillance of Congenital Anomalies 
Congenital Anomaly Registries in 12 European countries, with a population of 5.6 
million births during 1982-2011. Participants Cases included live births, fetal 
deaths from 20 weeks gestation, and terminations of pregnancy for fetal anomaly. 
Main outcome measures We estimated total prevalence per 10,000 births. Odds 
ratios for exposure to maternal illnesses/medications in the first trimester of 
pregnancy were calculated by comparing Ebstein's anomaly cases with cardiac and 
non-cardiac malformed controls, excluding cases with genetic syndromes and 
adjusting for time period and country.
RESULTS: In total, 264 Ebstein's anomaly cases were recorded; 81% were live 
births, 2% of which were diagnosed after the 1st year of life; 54% of cases with 
Ebstein's anomaly or a co-existing congenital anomaly were prenatally diagnosed. 
Total prevalence rose over time from 0.29 (95% confidence interval (CI) 
0.20-0.41) to 0.48 (95% CI 0.40-0.57) (p<0.01). In all, nine cases were exposed 
to maternal mental health conditions/medications (adjusted odds ratio (adjOR) 
2.64, 95% CI 1.33-5.21) compared with cardiac controls. Cases were more likely 
to be exposed to maternal β-thalassemia (adjOR 10.5, 95% CI 3.13-35.3, n=3) and 
haemorrhage in early pregnancy (adjOR 1.77, 95% CI 0.93-3.38, n=11) compared 
with cardiac controls.
CONCLUSIONS: The increasing prevalence of Ebstein's anomaly may be related to 
better and earlier diagnosis. Our data suggest that Ebstein's anomaly is 
associated with maternal mental health problems generally rather than lithium or 
benzodiazepines specifically; therefore, changing or stopping medications may 
not be preventative. We found new associations requiring confirmation.