Congenital malformations in mice after gonadotropin-induced ovulation.

Virgin mice were treated with gonadotropic hormones in order to induce superovulation; at term the embryos were removed by cesarean section. This treatment induced malformations (mainly forelimb defects and to a smaller extent central nervous system anomalies) as well as an altered sex ratio in the offspring. Both phenomena were statistically significant. These hormone-induced effects on the progeny were significantly dependent on both the dosage of hormones and the time (season) of administration. Because the time of administration (before mating) of gonadotropic hormones does not coincide with the critical period during embryogenic development for the teratogenic induction of malformations in the limbs and in the central nervous system (ca. 8th-12th day of gestation), the investigated defects are interpreted as of mutagenic origin.