Serum Heat-stable Alkaline Phosphatase and Placental Function

Abstract

The pattern of serum heat-stable alkaline phosphatase (HSAP) of women in late pregnancy was examined and discussed in relation to the clinical course. Four types were recognized in the HSAP pattern. The unstable type was most closely related to the clinical course; that is, this type was observed in only 6 out of 79 cases of the normal group, whereas it was found in 12 out of 24 of the postdated group and 5 out of 10 of the toxemia group. The incidence of intra-uterine fetal distress and of placental dysfunction syndrome was also highest in the unstable type. The significance of the unstable type was stressed as an alarm signal for fetal life in the third trimester of pregnancy.