Teratogenic effect of hyperthermia during early organogenesis period in mice.

Pregnant Swiss albino mice were subjected to 41, 42, or 43 degrees C temperature for 10 minutes on day 6.5 of gestation. Another group of animals treated at 37 degrees C was used as control. All animals were killed on the 18th day of gestation and fetuses were examined for prenatal mortality, growth retardation, and microphthalmia incidence. Results indicated a dose dependent increase in the mortality rates with a 42% death in the 43 degrees C group. Treatment with the higher temperatures (42 and 43 degrees C) resulted in a significant increase in the number of growth retarded fetuses and in the incidence of microphthalmia. Reduction in head length and decrease in brain weight were observed in the group exposed to 43 degrees C, particularly in the growth retarded fetuses. However, the percent brain weight(g)-body weight(g) ratio did not show any significant difference from the control values.