Liver and kidney ultrastructural changes caused by acetylsalicylic acid treatment during pregnancy in rats.

The worldwide use of acetylsalicylic acid (ASA) as an analgesic-antipyretic drug, including during pregnancy, prompted us to investigate its potentially deleterious effects in that condition. Pregnant rats were treated with ASA (1, 10 or 100 mg/kg once a day) from the first day up to term pregnancy. No histological changes were noticed in maternal and fetal livers or kidneys when examined under light microscopy, but some definite dose-dependent effects of ASA were observed on electron microscopy examination. In livers and kidneys of pregnant rats treated with the highest doses of ASA we observed cytoplasmic derangement, mitochondrial cristolysis and abnormally shaped rough endoplasmic reticulum. Similarly, in foetal livers and kidneys from this group we observed degenerative cytoplasmic vacuoles and ballooned mitochondria with cristae derangement and myelin figures. Our data point out the fact that both maternal and foetal tissues can be importantly affected by ASA at the ultrastructural level, without overt signs of toxicity.