The effects of phenytoin on rat development: an animal model system for fetal hydantoin syndrome.

An animal model system has been established which reproduces some of the features of the Fetal Hydantoin Syndrome. This pattern of altered growth and development includes growth retardation, craniofacial anomalies, distal phalangeal hypoplasia, and mental deficiency. Rats exposed in utero to phenytoin on gestational days 9, 11, and 13 exhibited fetal onset growth retardation, abnormalities of the craniofacial region and axial skeleton. In addition, the exposed offspring had significantly lower fetal weights, a shortened snout and a high-arched, irregular palate, and significant delays in skeletal maturation. These abnormalities resemble those reported for the Fetal Hydantoin Syndrome and provide a means to study the effect of phenytoin on the morphological and biochemical development of the fetus.