The technological revolution we witness today poses a threat to the homosapiens species, and its biological results are unpredictable. Excess toxic metals in the environmentand the deficiency of bio-elements are particularly harmful for developing organisms. Long-term fetalexposure during pregnancy to even lower concentrations of toxic metals, which have the ability to accumulate,often leads to irreversible developmental disorders, On the basis of accessible literature, the paperpresents transplacental transmission of cadmium, lead and mercury to the fetus. The disadvantageous effectsof cadmium and lead on ionic transmission, functional potential and submicroscopic amnion structure aswell as the interdependence between the unfavorable effects of these two metals on the amniotic membraneand the competitive antagonistic activity of Mg ions are emphasized. This paper presents a hypothesissuggesting the involvement of cadmium in the etiopathogenesis of eclampsia based on the literature. Italso considers the present state of knowledge of the toxic effects of Cd, Pb and Hg on the course ofpregnancy and fetal development. Magnesium--an intracellular cation second in importance to potassiumplays a significant biological role, though it has not been fully explored yet. The concentration ofMg in the placental and fetal tissues increases during pregnancy. The requirements for this element ina pregnant woman's organism generally exceed its supply; hence, pregnancy should be considered a conditionof 'physiological hypomagnesemia'. The accessible data concerning the content of Mg during pregnancyin the blood as well as in the uterine muscular wall in physiological and pathological pregnancies arediverse. The prevailing opinion is that oral supplementation of magnesium during pregnancy makes up forits deficit in the organism of the pregnant woman and also positively influences fetal development. Itis recommended to administer magnesium with food in the form of magnesium salts at the dose 5 mg/kg bodymass daily. In clinical obstetric practice magnesium therapy is necessary in cases of imminent pretermbirth and preeclampsia. This paper discusses the mechanism and therapeutic effectiveness of magnesiumsulfate as used in complications of pregnancy. The contamination of the pregnant woman's organism bytoxic metals--cadmium, lead and mercury--poses a serious risk of the same quantitative degree of contaminatingthe organism of the child developing in her womb. Qualitative changes may be much more serious in thefetus as they affect young structures, intensively developing, with no well-formed defense mechanisms.It is also worth mentioning that the complications in the course of pregnancy may result from toxic metalconcentrations lower than those leading to fetal necrosis or premature termination of pregnancy.

Keywords: Pregnancy, microintoxication, Cadmium, Lead, Mercury, Magnesium, Competition, therapy