Epidemiology of Ebstein anomaly: prevalence and patterns in Texas, 1999-2005.

Ebstein anomaly is a rare but serious cardiac defect, however, little is known about the etiology of this condition. The goal of this study was to expand our limited understanding of the epidemiology of Ebstein anomaly. Data for cases with Ebstein anomaly, as well as all live births, were obtained from the Texas Birth Defects Registry (TBDR) and Center for Health Statistics for the period 1999-2005. Descriptive analyses and estimates of birth prevalence and crude prevalence ratios were used to characterize this defect in Texas during the study period. There were 188 definite cases of Ebstein anomaly identified in the TBDR. The overall prevalence was 0.72 per 10,000 live births. Variables associated with an increased prevalence of non-syndromic Ebstein anomaly included: maternal age >39 years (compared to those 20-24 years), maternal residence along the Texas-Mexico border (compared to non-border residence), and conception in fall or winter (compared to summer). In addition, infants with Ebstein anomaly were at a greater risk of preterm birth and being small for gestational age. These findings help to define subgroups of women at increased risk of having offspring affected by Ebstein anomaly. Furthermore, our findings add to the limited body of literature on this rare but serious malformation.