[Alkaline phosphatase in the leukocytes of women with a normal pregnancy]

280 women were studied--30 of whom were nonpregnant and 250 were pregnant at various periods of normal progressing pregnancy. The activity of leucocytic alkaline phosphatase was determined cytochemically. It was established that the activity of the enzyme was elevated even at the earliest periods of pregnancy compared with the activity of nonpregnant women. The activity increased continuously up to 25-27 week's gestation. After this period up to 35-37 week's gestation the activity of leucocytic alkaline phosphatase was constant. New elevation of enzymic activity was established at the term of pregnancy. Possible causes for the observed changes were discussed. Reference values for the activity of leucocytic alkaline phosphatase during the second half of normal progressing pregnancy are described.