The present invention provides a method of predicting pregnancy outcome in a subject by determining the amount of an early pregnancy associated molecular isoform of hCG in a sample. The present invention further provides a method for determining the amount of early pregnancy associated molecular isoforms of human chorionic gonadotropin (hCG) in a sample. The present invention also provides a diagnostic kit for determining the amount of early pregnancy associated hCG in a sample. The present invention additionally provides an antibody which specifically binds to an early pregnancy associated molecular isoform of human chorionic gonadotropin. Finally, the present invention provides methods for detecting trophoblast or non-trophoblast malignancy in a sample.