Magnesium content of human myometrium and placenta during various stages of gestation, and of different body fluids at term.

Pregnancy is marked by a state of hypomagnesaemia but not much is known about the effects of maternal magnesium deprivation on the fetus. The aim of this study was therefore to measure magnesium concentrations in human myometrial and placental tissues and in different body fluids during pregnancy and at term, using atomic absorption spectrophotometry. The magnesium concentration in umbilical cord blood was higher than in the maternal blood, supporting the existence of an active magnesium transport system. There was also a difference between the magnesium concentration in the amniotic fluid and that in the umbilical cord blood. The magnesium content of myometrium increased from the 32nd week of pregnancy, reaching its maximum level at the 37th week of gestation. Later there was significant decrease in magnesium level until the end of pregnancy. The magnesium content of placental tissue did not change up to the 30th week of pregnancy; however, it then decreased continuously during the last trimester. The significant improvement experienced in certain pathological conditions of pregnancy treatment with magnesium supports the existence of a magnesium deficit induced by pregnancy and the need for magnesium supplementation.