Use of Curves for Prediction of Maternal Blood Levels of Placenta-Specific Substances for Diagnosis of Placental Function

Maternal blood levels of cystine aminopeptidase (CAP), human placental lactogen (HPL) and β1 glycoprotein (SP-1) were predicted and evaluated using the expressions and thier charts developed by us to help diagnosis of placental function in women of the third trimester of pregnancy. This study was conducted on the assumption that these placenta-originating substances as markers would behave similarly to the previously reported heat-stable alkaline phosphatase (HSAP). The results realized the following features: (1) CAP, HPL and SP-1, like HSAP, had their normal ranges of values too wide to be based on for diagnosing placental function in general, but it was confirmed that on the individual basis these marker substances could develop adequate “prediction curves” for their values to come well answering to the test in the same way as with HSAP. (2) The expressions for predicted values revealed that these marker substances in their shift in the maternal blood had different critical points start of deviation from exponential rising. Particularly in abnormal pregnancy, their shifting patterns were often dissimilar to one another, with implications that impaired placental function could possibly be confirmed qualitatively by reference to the predicted curve for the values of either of the marker substances.