Objective: The purpose of this study was to determine whether maternal Lyme disease increases the risk of congenital heart defect.
Study design: This retrospective case-control study was carried out at a medical center in a suburban area where Lyme disease is endemic. Case patients comprised 796 children with a diagnosis of congenital cardiac anomaly. Control subjects comprised 704 children without cardiac defects selected from the records of the same pediatric cardiology service. Maternal histories were obtained through a mailed questionnaire survey. Unconditional logistic regression analyses examined the relationship between a history of preconception and prenatal clinical Lyme disease or tick bite and case or control status.
Results: There was no association between congenital heart defect and maternal tick bite (adjusted odds ratio 1.1, 95% confidence interval 0.5-2.5) or maternal Lyme disease within 3 months of conception or during pregnancy (adjusted odds ratio 0.9; 95% confidence interval 0.2-3.6).
Conclusion: A woman who has been bitten by a tick or is treated for Lyme disease during or before pregnancy is not at increased risk for giving birth to a child with a congenital heart defect.