OBJECTIVE The objective of the study was to determine whether female veterinarians have an increased risk of spontaneous abortion and whether the potential risk is related to the type of work veterinarians do. METHODS The investigation was a retrospective cohort study among all the female members of the Finnish Veterinary Association (N=549). Information on pregnancies was obtained from hospital records from 1973-1990. The risk of spontaneous abortion among the veterinarians was compared with that of all other Finnish women and other upper-level employees. Odds ratios from logistic regression analyses were used as the estimates of the risk ratios. RESULTS The risk of spontaneous abortion was 10.5% for the veterinarians. In the 1970s, practicing veterinarians had an increased risk of spontaneous abortion as compared with other Finnish women (adjusted odds ratio 1.8, 95% confidence interval 1.0-3.1) or other upper-level employees (adjusted odds ratio 2.0, 95% confidence interval 1.1-3.4). In the 1980s, the risk fell below that of other Finnish women. No essential differences were observed in the risk between the veterinarians employed in different occupational categories. CONCLUSIONS The results suggest that the veterinarians had an increased risk of spontaneous abortion in the 1970s, but not in the 1980s. Factors which might have contributed to this decrease in risk include decreases in the prevalence and level of exposure to harmful agents, improvements in the occupational hygiene of the work environment, and an increased awareness of reproductive hazards and the use of sick leave during pregnancy.