Three growth models were used to examine the effects of prenatal exposure to aspirin on the postnatal development of brain parts. A total of 60 pregnant rats which were divided into three experimental groups and a control group were exposed to aspirin doses of 12.5, 25, 37.5 mg/kg, and distilled water, respectively. The brain parts of 200 rat pups starting from the first week after birth until the fifth week were weighted and the length and width of the cerebrum and cerebellum were measured to determine the parameters of the growth models. The results indicated that the three models successfully predicted the growth of the different brain parts and that aspirin decreased the total brain weight, cerebrum length and width, and decreased the cerebellum length and width at aspirin dose of 37.5 mg/kg. Further analysis is needed to investigate if aspirin effects were carried out through its role in inhibiting prostaglandin production and consequently affecting the activity of the hypothalamus-pituitary axis.