Human chorionic gonadotropin levels in various compartments in disturbed early pregnancy.

The hCG level in the uterine cavity was higher than in peripheral blood in a case of choriocarcinoma and in patients with spontaneous expulsion of the conceptus. In two patients with missed abortion, the hCG concentrations in peripheral blood and in serum from the uterine cavity did not differ. In contrast, the hCG concentrations in PF in these patients were lower than in peripheral blood. The measurement of hCG in these compartments may provide evidence concerning the location of the trophoblast.