Taking into account the prevalence of preeclampsia, the severity of its possible complications, and its treatment difficulties, the development of methods for its prevention is of considerable interest. It is shown that there is a relationship of the development of pregnancy complications, including preeclampsia with magnesium deficiency. The use of organic magnesium salts (citrate) in combination with pyridoxine (Magne B6 Forte) to correct magnesium deficiency and to prevent of severe preeclampsia makes it possible to considerably reduce its incidence and severity and the rate fetoplacental insufficiency (FPI) and to improve the outcomes of pregnancy and labor and the neonatal status, as demonstrated by this study including 277 pregnant women. The frequency of diagnosed pregnancy complications was significantly higher in the group of women not receiving Magne B6 Forte as part of combination therapy. The efficacy of magnesium citrate used in combination with pyridoxine to replenish magnesium deficiency was most clearly manifested in women with a history of recurrent miscarriage and with preeclampsia and FPI during previous pregnancies. No adverse events and side effects were recorded. Thus, preeclampsia prophylaxis and combination therapy using Magne B6 Forte in pregnant women with preeclampsia and FPI are highly effective and safe, which allows them to be recommended for the prevention and pharmacological correction of preeclampsia.