Background: Major birth defects are important infant outcomes that have not been well studied in the postmarketing surveillance of vaccines given to pregnant women. We assessed the presence of major birth defects following vaccination in the Vaccine Adverse Event Reporting System (VAERS), a national spontaneous reporting system used to monitor the safety of vaccines in the United States.

Methods: We searched VAERS for reports of major birth defects during January 1, 1990, through December 31, 2014. We excluded birth defects from vaccines that had been studied in pregnancy registries or other epidemiological studies (e.g., human papilloma virus, varicella, measles/mumps/rubella, and anthrax vaccines). Birth defects were categorized into trimester of vaccination and classified based on the organs and/or systems affected. If several birth defects affecting different systems were described, we classified those as multiple body systems. Empirical Bayesian data mining was used to assess for disproportionate reporting.

Results: We identified 50 reports of major birth defects; in 28 reports, the vaccine was given during the first trimester; 25 were reports with single vaccines administered. Birth defects accounted for 0.03% of all reports received by VAERS during the study period and 3.2% of pregnancy reports; reported defects affected predominately the musculoskeletal (N = 10) or nervous (N = 10) systems. No unusual clusters or specific birth defects were identified.

Conclusion: This review of the VAERS database found that major birth defects were infrequently reported, with no particular condition reported disproportionally. Birth defects after routine maternal vaccination will continue to be monitored in VAERS for signals to prompt future studies. Birth Defects Research 109:1057-1062, 2017. © 2017 Wiley Periodicals, Inc.