HCG in pathologic pregnancy

Abstract

Abstract Immunologic methods have transformed the field of HCG assay. Biologic and immunologic assays may give rather different results. Immunologic techniques measure the spectrum of ‘gonadotropins’ different from that detected by biologic methods. The trend of values obtained by biologic tests is usually the same as that obtained in immunoassay. In pathologic pregnancy, variations of HCG concentrations reflect changing production rates rather than altered renal excretion. A fetal metabolism of HCG occurs. In general, there are wide inter- and intrapersonal fluctations of HCG. The use of serum HCG is of prognostic value in early threatened abortion, but not in late abortion. Increased HCG excretion is not necessarily associated with hydatidiform mole pregnancy. Determination of urinary solB I ratio can be a useful additional diagnostic step. Serum HCG is nearly always elevated in molar pregnancy. Serum HCG and/or urinary HCG titers are of paramount importance in the detection of choriocarcinoma following a mole, and in the clinical evaluation of patients submitted to chemotherapy. Intracranial or spinal cord metastases can be detected by HCG determinations in cerebrospinal fluid. Considerable amounts of HCG are excreted for several weeks after termination of intra-abdominal pregnancy with the placenta left in situ. There is a slowly declining production of HCG under these circumstances. Female fetuses are associated with higher HCG levels than male ones, which may suggest that the fetus exerts some control over placental HCG synthesis. In multiple pregnancy, urinary HCG excretion has been reported to be above or at the upper limit of normal values. Serum HCG is abnormally high or in the normal range. In hypertension without superimposed preeclampsia, the HCG excretion is in the normal range. The excretion values do not change prior to or at the moment of intrauterine fetal death. The balance of evidence suggests that the mean values of serum and urinary HCG are mostly higher in severe toxemia than in normal pregnancy. This is correlated with a higher placental concentration of HCG. Routine HCG assays are of no value in the clinical management of toxemia of pregnancy. In cases of severe Rh iso-immunization, the serum and urinary HCG values are increased, presumably because of the increased HCG production by the large and hydropic placenta. In terms of fetal viability, HCG determinations are of no value. In pregnancy complicated with diabetes there is no relationship between HCG levels in the body fluids and the outcome of pregnancy. In prematurity and in postmaturity, the excretion of HCG is in the normal range.