Magnesium and calcium concentration in the pregnant and non-pregnant myometrium

Objectives: To investigate the effect of labor on the magnesium and calcium concentrations in the human myometrium and to compare them with the concentrations in the non-pregnant uterus. Method: Samples of the isthmic part of the uterus were taken from 42 patients not in labor, 31 patients in regular labor during a cesarean section, and 37 premenopausal patients on whom a hysterectomy was performed. Results: (i) The magnesium concentration dropped significantly during labor; (ii) the calcium concentration in the tissue showed no significant changes during labor; (iii) the magnesium and calcium concentrations were significantly higher during pregnancy; (iv) the distribution of electrolytes in the myometrium differed significantly in the corpus, isthmus and cervix uteri. Conclusions: The electrolyte concentration in the myometrium depends on the place of removal. A low magnesium concentration in the pregnant human myometrium could be a cause of premature labor.