[Plasma and myometrium electrolyte changes in the last trimester of pregnancy].

It is well known, that magnesium can positively influence preterm labour and that the magnesium level in the plasma is significantly lowered whereby magnesium excretion increases during pregnancy. These results lead to the question, whether the magnesium content in the myometrium is also reduced during pregnancy and whether blood parameters correlate with the concentration of magnesium in the myometrium. Myometrial tissues and blood samples from 127 patients, who underwent a Caesarean section, were analysed for magnesium, calcium, sodium and potassium. Erythrocytes, haemoglobin, haematocrit and the hormones oestradiol, oestriol and progesterone were analysed in the serum. We found a decrease in magnesium in the myometrium (p < 0.01) and in the plasma (p < 0.05) during pregnancy. Magnesium in the plasma correlates with magnesium in the myometrium (p < 0.001). These results indicate, that hypomagnesinaemia during pregnancy decreases the magnesium level in the myometrium.