Fertility and irradiation: a preconceptional investigation in teratology.

The effects of preconceptional irradiation on female fertility were investigated in six groups of 35 nulliparous Swiss-Webster mice whole-body irradiated with single doses of 25, 50, 75, 100, 150, and 300 rads of 60Co. They were mated with nontreated males and killed on gestational day 18. The litters were recorded in the chronologic order of their occurrence within each group. The percentage of pregnancies decreased with the dose, while the prenatal loss increased. Up to 100 rads, the middle group of pregnancies was devoid of resorptions, fetal death, and congenital anomalies, thus giving rise to a "maximum viability enclave." Beyond this level those three adverse effects were more or less homogeneously distributed over the whole period for which pregnancies were recorded. Exencephaly, microcephaly, and eye defects were the most frequent malformations. Among other sequelae, hypertrophy of the higher pole occurred in the left kidney in the surviving infertile females killed 5 months after treatment.