Embryofetotoxicity of acetaminophen (paracetamol) in experimental in vivo model.

The aim of the study was to evaluate the toxic effect of acetaminophen on rat fetuses. Acetaminophen, suspended in Tween 80 solution, was administered once a day, orally by a stomach tube to pregnant Wistar rats from day 8th to 14th of pregnancy at the dose: 3.5 (P1), 35.0 (P2), 350.0 mg/kg (P3). The pregnant females were terminated on day 21st of pregnancy and the number of corpora lutea, implants, resorptions, and fetuses was counted. The fetuses and the placentas were weighed and the length of the fetuses and their tails were checked. The slides of the fetal liver were examined via light microscopy in four stains: hematoxylin and eosin, silver Gomorii, van Giesson, and periodic acid-Schiff. There was a statistical (p < 0.05) difference in fetal body length in group P3 without any macroscopic malformation, except for the non-statistical number of subcutaneous ecchymoses. Histological adaptive changes of the fetal liver were observed occasionally in all the studied groups. In conclusion, the oral administration of acetaminophen caused an embryotoxic effect in the highest doses without any macroscopic malformation, and only slightly impaired morphology of the rat fetal liver.