Plasma and Membrane Ca2+ and Mg2+ Concentrations in Normal Pregnancy and in Preeclampsia

Objective: Changes in intracellular Ca 2+ and Mg 2+ concentrations seem to be involved in the pathogenesis of preeclampsia, whereas the role of cell membranes has not been studied in detail yet. To investigate the changes in Ca 2+ and Mg 2+ metabolism in normal pregnancy and preeclampsia, plasma and membrane Ca 2+ and Mg 2+ concentrations were determined in a clinical study as compared to healthy subjects. Study Design: 25 healthy female subjects, 22 untreated healthy pregnant and 20 preeclamptic women were investigated. In each patient, plasma and membrane Ca 2+ and Mg 2+ content were measured. Ca 2+ and Mg 2+ concentrations were measured by atomic absorption spectroscopy. Erythrocyte membranes were chosen for membranous Ca 2+ and Mg 2+ determination. Results: Plasma Mg 2+ concentrations were significantly lowered in the healthy pregnant group and the preeclamptic group as compared to contols (p < 0.0001). In erythrocyte membranes, Mg 2+ content was found significantly decreased in the preeclamptic women as compared to healthy subjects (p < 0.001). In plasma Ca 2+ concentrations there was a significant decrease in the preeclamptic group as compared to controls or healthy pregnant women (p < 0.05). Membranous Ca 2+ content was significantly increased in the preeclamptic group versus controls or healthy pregnant women (p < 0.001). Conclusion: Lowered plasma and membrane Mg 2+ concentrations in preeclampsia may contribute to the development of hypertension in pregnancy. Additionally, a disturbed Ca 2+ homeostasis is observed in preeclampsia.