Measuring human chorionic gonadotropin for detection of early pregnancy loss.

Elucidation of the primary molecular structure of hCG, coupled with monoclonal antibody technology, has permitted the construction of a partial map of hCG surfaces. Based on this information, two-site immunoradiometric assays have been developed which permit the measurement of intact hCG and its subunit molecular forms with unprecedented sensitivity and specificity. These assays have been employed in a determination of the incidence of early pregnancy loss in a normal population with the finding that 22% of all conceptions producing measurable hCG terminate before becoming clinically evident.