Plasma, Intracellular, and Membrane Mg²⁺ Concentrations in Normal Pregnancy and in Preeclampsia

Abstract

Objective and Design: Decreased cellular Mg²⁺ concentrations seem to be involved in the pathogenesis of preeclampsia. To investigate the changes in Mg²⁺ metabolism in normal pregnancy and preeclampsia, plasma, intracellu-lar, and membrane Mg²⁺ concentrations were determined in a clinical study and compared to values of healthy nonpregnant subjects.

Subjects and Methods: Twenty-five healthy female subjects (nonpregnant), 22 untreated healthy pregnant women, and 20 preeclamptic women were investigated. In each patient, plasma, erythrocyte, and membrane Mg²⁺ content were measured. In the preeclamptic group, plasma and erythrocyte Mg²⁺ content were determined before and after a Mg²⁺ supplementation and 4–7 days after delivery.

Results: Plasma Mg²⁺ concentrations were significantly lowered in the healthy pregnant group and the preeclamptic group as compared to nonpregnant controls (P < 0.0001). In comparison with nonpregnant subjects, both healthy pregnant and preeclamptic women had significantly lowered intra-cellular Mg²⁺ concentrations, being more severe in the preeclamptic group (P < 0.0001). After Mg²⁺ supplementation in the preeclamptic group, plasma Mg²⁺ concentrations normalized (P < 0.0001), but intracellular Mg²⁺ deficiency could not be corrected completely. In erythrocyte membranes, the Mg²⁺ content was found significantly decreased in the preeclamptic women as compared to healthy pregnant and nonpregnant subjects (P < 0.001).

Conclusion: Lowered cellular and membrane Mg²⁺ concentrations in preeclampsia may contribute to the development of hypertension in pregnancy.

Key Words:

• Mg²⁺
• Hypertension
• Pregnancy
• Preeclampsia
• Membranes