EFFECT OF NORMAL PREGNANCY ON BIOCHEMICAL MARKERS OF

Biochemical markers of bone turnover are reliable indices for measuring changes in bone formation and bone resorption. Due to limitations in the use of bone densitometry during pregnancy, biochemical markers of bone turnover provide an excellent alternative to examine the state of the skeleton during this physiologic state. Pregnancy induces dynamic changes in maternal bone and calcium metabolism. Calcium and vitamin D play major roles in calcium homeostasis and skeletal development, especially during pregnancy.Adequate vitamin D concentrations during pregnancy are necessary to ensure appropriate maternal responses to the calcium demands of the fetus and neonatal handling of calcium. This adequacy is crucial during pregnancy to assure normal fetal skeletal growth and to provide the vitamin D needed for infant’s stores where there is inconsistent evidence that maternal 25-hydroxyvitamin D deficiency may impair fetal growth.This study was done to elucidate the effect of normal pregnancy on 25-hydroxyvitamin D3, calcium (total and free), phosphorus, magnesium and alkaline phosphatase, and to find any relation between these parameters. Eighty subjects were enrolled in this work, and were classified into two main groups; group-I comprising 20 apparently healthy non pregnant women and group-II including 60 pregnant women that were subdivided into 3 subgroups according to the stage of pregnancy. Conclusively, several hormonal and biochemical markers were known to affect bone metabolism. These markers have been shown to be changed with different stages of pregnancy. There was decrease in the plasma level of 25(OH)-vit-D3, free calcium and magnesium but there was increase in both plasma phosphorus and alkaline phosphatase activity. So, some biochemical markers of bone turnover have emerged as useful determinants of bone physiology.