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.