Luteotropic activity in serum of women following embryo or gamete transfer in a program of assisted conception

Abstract

In an attempt to track the proliferation/demise of trophoblastic tissues in women following gamete transfer (GT) or in vitro fertilization/embryo transfer (IVF/ET), we have measured levels of human chorionic gonadotropin (hCG) in serum of 180 patients on days 7 and 14 following oocyte pickup (OPU). Serum hCG levels were measured by immunoassay and by a bioassay based on the capacity of the sample to stimulate testosterone secretion by cultured mouse Leydig cells. Based on determinations of bioactive and immunoactive hCG in serum from 18 of 180 patients who subsequently delivered (12 of 73 GT, 6 of 107 IVF/ET;P0.05). The luteotropin bioassay described is highly sensitive to hCG (to 0.02 mIU/ml serum) and appears appropriate to the characterization of proliferation/demise of embryonic tissues during the 14 days after gamete/embryo transfer. In addition, through its representation of the cumulative luteotropic properties of human serum and its insensitivity to biologically inactive hCG subunits; this bioassay appears more appropriate than hCG immunoassay in the monitoring of early embryonic signalling following assisted (or spontaneous) conception in the woman.