[Alkaline phosphatase isoenzyme activity in the serum of women during the second half of pregnancy].

The authors determined total alkaline phosphatase activity as well as the activity of placental, bone marrow and liver isoenzymes in sera of 185 pregnant women with normal pregnancy, divided, into 6 groups according to their gestational age (from 20 to 40 weeks' gestation). It was established an increase of bone marrow and placental isoenzymes of alkaline phosphatase parallel to an increase of gestational age, while the values of liver isoenzyme were comparatively constant, with the exception at 34-36 weeks' gestation when was elevated. Inferences are made for the origin of hyperphosphatemia during pregnancy.