To investigate the mechanism of prolonged uterine hemorrhage after terminating early pregnancy by mifepristone plus misoprostol.Forty-five decidua specimens were obtained from 45 pregnant women with amenorrhea of 6-7 week duration. Fifteen women were treated with mifepristone and 15 were treated with mifepristone plus misoprostol. The remaining 15 served as controls. The tPA and PAI-1 mRNA levels were estimated by reverse transcription-polymerase chain reaction. Chromogenic assay and enzyme-linked immunosorbent assay were used to detect tPA activity and PAI-1 protein level in decidua.The activities of tPA in the mifepristone plus misoprostol group and in the mifepristone group were 46.91 +/- 20.74 IU/mg.protein and 64.25 +/- 35.81 IU/mg.protein respectively, lower than those in the normal decidua group (99.76 +/- 58.61 IU/mg.protein, P < 0.05). tPA mRNA levels in the mifepristone plus misoprostol group were the highest (1.43 +/- 0.39) among the groups. In the mifepristone group, tPA mRNA level (0.90 +/- 0.16) was not significantly different from that in the normal decidua group (0.94 +/- 0.17). The protein and mRNA expression levels of PAI-1 were not significantly different among the three groups (P > 0.05).Mifepristone plus misoprostol decreased tPA activity in human early decidua by post-transcription pathways, which may influence decidua shedding, endometrial angiogenesis, endometrial remodeling, and cause prolonged uterine hemorrhage after drug abortion.