This study sought to determine malformation caused by Ochratoxin-A (OTA) on mouse embryos. Twenty adult female white Swiss mice (mus msculus) were divided into four groups, with five females per group, and with one male placed with two females in a cage. Avaginal plug was observed in the early morning and the day of mating was considered as day of pregnancy followed by the first day of pregnancy. Three sub lethal concentrations of OTA were applied to the respective groups (other than the control), 1mg/kg, 2mg/kg and 4mg/kg. The animals were given 0.1 ml per 10 gm body weight per concentration of OTA once a day during days 7-14 of pregnancy. The control group animals were given distilled water. The pregnant mice were dissected, and the embryos were extracted in order to identify the effects of the OTA. Number of parameters were studied including, difference in body weight of the mice before mating and after the end of the experiment, the weights and lengths of embryo, as well as a study of embryo malformation. The study shows no significant differences in the mean body weight of the pregnant mice in the 1 mg/kg group, compared to control group. A significant (P<0.01) decrease in the body weight of the treated mice was observed in the 2mg/kg and the 4mg/kg groups. As for the weight of the embryos, there was a significant (P<0.01) decrease in the body weight of the embryos in the mothers treated with OTA in the 1 mg/kg and 2 mg/kg treatment groups. The embryos of the 4mg/kg group of pregnant mice could not be recorded since they had been resorbed into their mothers uteri. Similarly, the results of the study showed a significant difference in the mean length of the embryos bodies in the 1mg/kg and 2mg/kg groups, compared with the non-treated control group. Many malformations induced in the embryos in those groups where it was possible to examine the embryos 1mg/kg and 2mg/kg compared to control mouse embryos, included loss of tail, lack of eyes, cleft lip and exencephaly, as well as spina bifida, curvature of the trunk and there were also reduction defects of the limbs. The study concluded that OTA have teratogenic effects on mice embryos
