Abstract Congenital malformations such as exencephaly occur at a high incidence in non-obese diabetic (NOD) mouse embryos (Otani et al., 1987a). Using in vitro culture and embryo transfer, genetic predispositions as well as environmental factors were suggested to be the causes (Tatewaki et al., 1987).
Chromosomes of preimplantation embryos, cultured to transfer mutually between non-obese diabetic (NOD) and ICR mice, were analyzed as a clue to elucidate the cause of developmental anomalies. Among these preimplantation embryos, aneuploidy, mixoploidy and structural anomalies were found, but in incidence of chromosomal anomalies there was no significant difference, statistically, between preimplantation embryos from diabetic mothers and those from non-diabetic mothers. These findings are considered to show that no increase in developmental abnormality in chromosomes occurs during the preimplantation stage.