Abstract: OBJECTIVE: The optimal teratogenic aspirin dosage for SD rats was determined. METHODS: Pregnant SD rats were randomly assigned to an aspirin dosage group(260, 270, 280, or 300 mg/kg aspirin) or to the negative control group. The indicators of teratogenicity examined included the following: the number of live fetuses, dead fetuses and reabsorbed fetuses, the appearance of the fetuses, and abnormalities in the development of the fetal skeletons and internal organs. RESULTS: Daily aspirin doses of 270, 280, or 300 mg/kg had substantial teratogenic effects on SD rats. The rates of abnormal development and malformations of the fetal skeletons and internal organs among the treated groups was dramatically elevated compared to the negative control group. However, the administration of a 260 mg/kg daily dose of aspirin did not induce appearance and internal organs malformations in rat fetuses. In addition, the study groups with doses of 280 and 300 mg/kg also produced maternal reproductive toxicity in the form of decreased number of live fetuses and a marked increase in the number of absorbed and dead fetuses. CONCLUSION: The optimal aspirin dosage for use as a teratogenic material in SD rats is 270 mg/kg.

Key words: aspirin, teratogenesis, dosage