The effects of nitrous oxide on the developing hamster embryos.

Pregnant hamsters were exposed to different concentrations of nitrous oxide during the period of organogenesis. Teratogenic effects were observed in a small but significant number of fetuses. Types of malformations included cleft palate, limb defects, gut herniation, and fetal edema. A dose-effect relationship was not observed. It is not clear from our observations whether the observed effect on the fetuses was due to the excess of nitrous oxide, hypoxia, or a combination of both. Comparison with published literature indicates that further studies on the effects of nitrous oxide in placental animals are needed.