Ifosfamide (50 mg/kg, i.p.) treatment before mating increases percentage of post-implantation loss and resorbs fetuses in pregnant rats. Ifosfamide also (50 mg/kg, i.p.) decreases the progesterone in the serum of pregnant rats. However, Ifosfamide causes no obvious difference with the control rats at 25 mg/kg. Ifosfamide (25, 50 mg/kg, i.p.) induces apoptosis and histological changes in the placentas and prenatal rats, most sensitive fetal organs are the brain, liver and kidney.