Comparative prognostic value of serum placental and tissue oxytocinase, alkaline phosphatase and its heat-stable fraction in pregnancy at neuroendocrinological risk.

Serum enzyme determinations are now well-established diagnostic tools in so-called "placental insufficiency". A good predictability of oxytocinases (P-CAP-placental oxytocinase and T-CAP-tissue oxytocinase) and a doubtful one of those of phosphatases (AP-alkaline phosphatase, HSAP-heat stable alkaline phosphatase) has been shown in high-risk pregnancies. The purpose of this study was to determine the prognostic value of the above cited enzymes in the so-called "pregnancy at neuroendocrinological risk", i.e. pregnancy in women with a prepregnancy history of hormonal disorders. It was shown that the outcome and results of such pregnancies are poorer that those of normal pregnancies. The series studied comprised 364 pregnant patients with pregnancy at neuroendocrinological risk that were being monitored by means of serum assays of the four enzymes. An attempt was made to assess each of these enzyme activities both in single (at least one value below 2.5 percentile calculated for healthy subjects) and serial determinations (two consecutive results decreasing or remaining at the same level). Normal and abnormal enzyme results were compared with normal and abnormal conditions of the newborn. The results presented showed that P-CAP (Tab. I) and T-CAP (Tab. II) levels were useful in prenatal diagnosis of fetal impairment in heneral, in addition to perinatal mortality and low values of the APGAR score. Neither the single nor serial assays of AT (Tab. III) and HSAP (Tab. IV) were valuable in predicting birth of an impaired neonate. Sensitivity of the test, i.e. percentage of women with abnormal enzyme assays among those patients who gave birth to impaired neonates, and specificity of the test, i.e. the percentage of women delivered of impaired neonates among all women with abnormal enzyme assays, of the four enzymes were compared. Sensitvity and specificity of P-CAP and T-CAP were higher than those for AP and HSAP. Moreover, sensitivity for all four enzymes was higher in serial assays, and specificity was higher in single assays. The results of the present analysis demonstrated the prognostic value of oxytocinase assays also in the pregnancy at neuroendocrinological risk. Assays of P-CAP and T-CAP were of equal significance, notwithstanding reports of a greater usefulness of P-CAP. Assays of CAP were helpful particularly in the conditions on which neuroendocrinological gestosis exerts a direct influence, i.e. in low Apgar score and perinatal mortality. On the other hand, serum alkaline phosphatases proved useless in endocrine pathology of pregnancy and HSAP was not superior to AP. About one half of future mothers of impaired neonates had enzyme results outside the range of the assays under consideration. This could be explained by the fact that these enzymes activities reflect placental function and are not directly related to fetal metabolism. Because of that they should be supplemented by other diagnostic methods being used in a clinic of high-risk pregnancy.