The aim of this paper was to perform a randomized, controlled and blinded study to investigate if a therapeutic dose of acetylsalicylic acid (ASA), taken by pregnant women, may also cause embryotoxic or congenital abnormalities on experimental animal. METHODS: Females were confirmed to have mated by observations of sperm in a vaginal smear. The day on which spermatozoa were found in the vaginal smear was considered as day 1 of gestation (GD1). After randomization, mated females were assigned to experimental groups and individually caged, were given 50 mg/kg/day of acetylsalicylic acid, by needle gavage once daily, during two different periods of pregnancy. One group of dams (n=11) received aspirin from day 1 to 4 of pregnancy (before embryonic implantation) for evaluation of the blastocysts, and another group received aspirin from day 6 to 15 of pregnancy (organogenic period) for fetal evaluation. Control groups (n=12) received distilled water in same volume and during same periods as their respective experimental groups. RESULTS AND CONCLUSION: The treatment of the dams with ASA, according to minimal therapeutic dose used for humans, did not cause embryotoxic or major malformations on experimental animal but was responsible for rate increased of fetuses presenting ureteric dilatation. After analysis of the data, it appears that, although direct conclusive evidence of adverse effects in humans is lacking, a potential hazard dose exists and thus the indiscriminate use of acetylsalicylic acid (aspirin) is contraindicated.
Aspirin; Acetylsalicylic acid; Pregnancy; Preimplantation; Rat
