Distribution and effects of DDT in the pregnant rabbit.

1. After administration of p, p'-DDT to pregnant rabbits DDT and its metabolites are found in high concn. in both the foetus and the organs of the maternal rabbit which regulate the foetal environment.2. p.p''-DDT does not rapidly leave the foetal tissue, as whole body levels at day 26 (17 days after DDT dosing) are higher than those in foetal plasma; foetal whole body levels are also higher than those found in placenta or maternal plasma, and half of those of maternal liver.3. p.p'-DDT treatment of pregnant rabbits at doses of 10 and 50 mg/kg caused an increased incidence of prematurity, an increase in the number of foetal resorptions and a decrease in foetal weight.4. These doses of DDT did not increase the incidence of chromosomal aberrations in the maternal or foetal tissue and exposure in vitro to levels as high as 100 μg/ml caused no abnormalities.