[Bone metabolism in pregnant women]

Serum ionized calcium, tartrate-resistant acid phosphatase (TR-ACP) and alkaline phosphatase (ALP) were measured in 80 pregnant women in different gestational weeks. The results showed that calcium level decreased significantly as the gestation week increased. Calcium level of umbilical cord was higher than that of third trimester of pregnancy. It indicated that calcium could be transported to fetus across the placenta against the concentration gradient. Both TR-ACP and ALP activity elevated as gestation week increased. This may suggest that the bone metabolism is very active in pregnant women.