Alterations in vitamin D and calcium metabolism with magnesium sulfate treatment of preeclampsia.
OBJECTIVE
Our purpose was to determine the effects of magnesium sulfate therapy on preeclamptic women and their fetuses with regard to the hormones and ions involved with calcium homeostasis, including 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D, parathyroid hormone, and calcium.


METHODS
The study group comprised 15 preeclamptic women at term treated with magnesium sulfate during labor. Controls were seven normal women in term labor. The hormones and ions were measured in maternal blood obtained at the onset of labor and at delivery and in umbilical venous (fetal) blood.


RESULTS
Baseline maternal levels of 25-hydroxyvitamin D and parathyroid hormone were lower in preeclamptics than in controls. Magnesium infusion led to significant elevations in magnesium, 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D, and parathyroid hormone levels and lowered calcium concentrations. Fetuses of treated subjects demonstrated reductions in serum total and ionized calcium and elevations of 1,25-dihydroxyvitamin D and parathyroid hormone.


CONCLUSIONS
Magnesium sulfate infusion causes reductions in both maternal and fetal calcium levels. Both mother and fetus respond with increased 1,25-dihydroxyvitamin D and parathyroid hormone levels, which may prevent more severe maternal, fetal, and neonatal hypocalcemia.
Cruikshank
D P
DP
Department of Obstetrics and Gynecology, University of Utah School of Medicine.
Chan
G M
GM
Doerrfeld
D
D
D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood*; D005260:Female; D005333:Fetus / Q000187:drug effects / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D008278:Magnesium Sulfate / Q000627:therapeutic use*; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D011225:Pre-Eclampsia / Q000097:blood / Q000188:drug therapy*; D011247:Pregnancy; D014807:Vitamin D / Q000097:blood*
D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; D008278:Magnesium Sulfate; D002117:Calcitriol; D002118:Calcium