Effects of the Chronic Use of Acetaminophen on Pregnant Rats - Revista Brasileira de Ginecologia e Obstetrícia

Purpose: to evaluate the effects of acetaminophen on the pregnancy of female albino rats. Methods: forty pregnant rats were separated into four groups. All the animals received daily by gavage 1 ml of acetaminophen solution from the first day (day zero) until the 20th day of pregnancy: group I – only distilled water (control); groups II, III and IV, respectively, 125, 500 and 1,500 mg/kg body weight of acetaminophen dissolved in distilled water. The animals were weighed on days 0, 7, 15 and 20 of pregnancy. Results: our results showed that the rats that received the medication presented a reduction in weight when compared to the control group. The incidence of reabsorption of the embryos was 2.0, 3.5 and 7.0 times higher than in the control, in groups II, III and IV, respectively. Groups GII and GIV showed a clear reduction in the weight of the concepts. In GIV there was a 50% reduction in weight increase of fetuses and placentas when compared to the control, and 15.7% of external malformations were also found. Conclusions: the continuous use of acetaminophen should be avoided at doses higher than 70 mg/kg per during pregnancy.