Relationship between prepregnancy anthrax vaccination and pregnancy and birth outcomes among US Army women.

CONTEXT: Substantial concern surrounds the potential health effects of the anthrax vaccine, particularly the potential adverse effects on reproductive processes.

OBJECTIVE

To determine whether receipt of anthrax vaccination by reproductive-aged women has an effect on pregnancy rates.

DESIGN, SETTING, AND PATIENTS: Cohort study, based on information from a computer database, of women aged 17 to 44 years who were stationed at Fort Stewart, Ga, or Hunter Army Airfield, Ga, from January 1999 through March 2000.

MAIN OUTCOME MEASURES: Pregnancy and birth rates and adverse birth outcomes.

RESULTS

Of a total of 4092 women, 3136 received at least 1 dose of the anthrax vaccine. There was a total of 513 pregnancies, with 385 following at least 1 dose of anthrax vaccine. The pregnancy rate ratio (before and after adjustment for marital status, race, and age) comparing vaccinated with unvaccinated women was 0.94 (95% confidence interval [CI], 0.8-1.2; P =.60). There were 353 live births and 25 pregnancies lost to follow-up. The birth odds ratio after anthrax vaccination (before and after adjustment for marital status and age) was 0.9 (95% CI, 0.5-1.4; P =.55). After adjusting for age, the odds ratio for adverse birth outcome after receiving at least 1 dose of anthrax vaccination was 0.9 (95% CI, 0.4-2.4; P =.88). However, this study did not have sufficient power to detect adverse birth outcomes.

CONCLUSION

Anthrax vaccination had no effect on pregnancy and birth rates or adverse birth outcomes.