Abstract: There are many maternal serum markers investigated in attempts to predict the outcome of pregnancy. The research of maternal serum markers emphasizes on threatened abortion in recent years， such as human chorionic gonadotrophin（hCG）， progestogen， estrogen， CA125， inhibin A，activin A， pregnancy-associated plasma protein-A， cytokine， and so on. Those maternal serum markers could be useful in guiding treatment and evaluating the effectiveness of therapy and predicting adverse pregnancy outcome in women of threatened miscarriage. It can avoid blind tocolyis and resulting in missed abortion. Meanwhile， it also can avoid the waste of medical resource. Thus there is very great clinic significance in diagnosis and therapy for threatened abortion.

Key words: Abortion, threatened, Biological markers, Chorionic gonadotropin, Inhibins, Activins