Serum alkaline phosphatase in pregnancy. II. Serial HSAP65degreesC estimations in pregnancy complicated with hypertension and pre-eclampsia.

This is a study of heat-stable alkaline phosphatase (HSAP65degreesC) concentrations in the serum of pregnant women with hypertension (42 cases), mild preeclampsia (40 cases) and severe pre-eclampsia (22 cases). The results are seen in relationship to the occurrence of intrauterine fetal death, growth retardation, intrauterine and neonatal asphyxia as well as the respiratory distress syndrome (RDS) in the newborn. The importance of a precise clinical classification of the patients is stressed. Pathological HSAP values are those which lie either over or under the normal range for HSAP activity. In addition "zig-zag" curves with values within the normal range are characterized as abnormal. Thus, serial estimations give the most reliable results. Serial estimations of HSAP are especially valuable in severe pre-eclampsia. Abnormal HSAP values in the 28th-38th week of pregnancy are a serious prognostic sign. False abnormal HSAP results were found in all 3 patient groups. One possible false normal HSAP curve also occurred.