Increased absorption of and sensitivity to cadmium during late pregnancy: is there a relationship between markedly decreased maternal cadmium binding protein (metallothionein) and pregnancy-induced hypertension?

Laboratory animals have a unique sensitivity to cadmium toxicity in late pregnancy. This acute toxicity is not seen in non-pregnant, early pregnant, or lactating animals. Furthermore, during late pregnancy, laboratory animals absorb and retain substantially more cadmium from their diets than they do in the non-pregnant state. Both of these observations parallel the fact that a fivefold late gestational drop of maternal metallothionein (a metal-binding protein believed to detoxify cadmium) has been demonstrated in pregnant animals. Additional factors such as nutritional status and age affect cadmium absorption. As we have discussed previously, cadmium toxicity and toxemia of pregnancy have many common features including hypertension, proteinuria, edema, vasospasm and endovasculitis. Because of the above, we propose that cadmium plays a role in the etiology of toxemia.