INHALATIVE CADMIUM EFFECTS IN PREGNANT AND FETAL RATS

Pregnant and non-pregnant rats were continuously exposed for 21 days to an aerosol containing 0.2, 0.4 and 0.6 mg cadmium/m3 air. Pregnant and non-pregnant rats exposed to clean air served as controls. The aerosol was generated by an ultrasonic nebulizer and was carried into inhalation chambers. The median aerodynamic diameters were on the order of 0.6 μm. After inhalation of cadmium aerosols serum iron levels were not lowered significantly in adult rats. A polycythaemic response of non-pregnant rats was observed due to a direct stimulatory effect of cadmium on erythropoiesis. Polycythaemia was less marked in pregnancy, presumably due to iron loss to placenta and fetus. Disturbances of pulmonary gas exchange or decreased plasma volumes were excluded as causative mechanisms of polycythaemia. In pregnant rats there was a marked dose dependent decrease of the activity of the alkaline phosphatase after cadmium inhalation, while there was no effect in exposed non-pregnant rats. This decreased enzyme activity, together with slowed growth rates and hemolytic effect indicate a higher sensitivity to cadmium in pregnancy. Proteinuria was not found in neither pregnant nor non-pregnant rats. Therefore, it is concluded that in this respect cadmium intoxication by inhalation does not resemble human toxemia of pregnancy, as discussed in the literature. The most sensitive parameter after inhalative cadmium exposure proved to be total wet lung weight. Fetal growth rates were reduced at the highest aerosol concentrations, in spite of a relative effective placental barrier to cadmium. The activity of the fetal alkaline phosphatase increased with increasing maternal cadmium exposure. © 1978.