Bioactive to immunoreactive ratio of circulating human chorionic gonadotropin as possible evaluation for the prognosis of threatened abortion

Objective: In an effort to evaluate the prognosis of threatened abortion, we established the ratio of serum human chorionic gonadotropin (hCG), as measured by bioassay or radioimmunoassay techniques, of samples from patients with threatened abortion or normal pregnancy. Study design: Peripheral blood samples from patients in their first trimester of pregnancy with threatened abortion (n = 24), or normal pregnancy (it = 12), were assayed for progesterone (RIA), and for immunoactive (DELFIA) and bioactive (mouse Leydig cell testosterone production assay) hCG. Results: Serum progesterone was not statistically different between the threatened-continuing and the threatened-miscarried groups. The ratio of hCG bioactive/hCG immunoactive (B/I) was significantly lower for the patients of the threatened group that experienced abortion. The B/I ratio for the control and threatened-continuing patients was similar. Conclusion: The hCG bioactive/hCG immunoactive ratio could be a good indicator of the prognosis of threatened abortion. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.