Abstract: To investigate the effect and safety of antifibrinolytics on decrement of postpartum blood loss. One hundred and twenty cases of primipara of vaginal delivery were randomly divided into tranexa mic acid group(Group A: pitocin+tranexamic acid), aminomethylbenzoic acid group(Group B: pitocin+aminomethylbenzoic acid)and pitocin group(Group C: pitocin). The postpartum blood loss was collected and measured carefully within the third stage of labor and forth stage of labor. Fibrinogen and D dimer were examined during antepartum(first stage of labor), half an hour postpartum and 2 hours postpartum. Result: ①The postpartum blood loss during the forth stage of labor in Group A was significantly lower than that in Group C(P<0.01), the total postpartum blood loss of Group A was significantly lower than Group C(P< 0.05). ②Fibrinogen among groups and at different times was not statistically different(P >0.05). D dimer was significantly different(P<0.001). In the Group A, D dimer of 2 hours postpartum was significantly higher than that of antepartum(P<0.05), but was not statistically significant with that of half an hour postpartum; in Group B, D dimer of half an hour and 2 h of postpartum was all significantly higher than that of antepartum(P<0.05); in the Group C, D dimer of 2 hours postpartum was higher than that of half an hour postpartum(P<0.05), and was significantly higher than that of antepartum(P<0.01), and was higher than that of 2 hours postpartum in Group A(P<0.05). ③No thromboembolism appeared in any of the three groups. Conclusion:Based on pitocin, proper antifibrinolytics can depress the rise of D dimer and decrease postpartum blood loss.

Key words: antifibrinolytics, postpartum blood loss, tranexamic acid, aminomethylbenzoic acid, fibrinogen, D dimer