Objective　To investigate the effect of mifepristone on the expression of tumor necrosis factor-α（TNF-α） and transforming growth factor-β（TGF-β）in decidua of early pregnancy. Methods　Thirty artificial abortion women as control and thirty drug abortion women were enrolled for study. The expressions of TNF-α and TGF-β in decidua were measured with immunohistochemical method. Results　There was no significant difference of TNF-α positive expression rates between drug abortion group (73.33%) and artificial abortion group (70.00%，P>0.05). TGF-β expression rate of drug abortion group was similar to that of artificial abortion group. The highly-positive (+　+ and +　+　+) TNF-α expression rate in drug abortion group was significantly higher than that in artificial abortion group (P<0.05). TGF-β expression degree in decidua of drug abortion group was significantly lower than that of artificial abortion group (P<0.05). The ratio of TNF-α/TGF-β in drug abortion group is higher than that in artificial abortion group. Conclusion　TGF-β has great effect on regulating the embryo development of early pregnancy. The change of TNF-α may be the reason of abortion. Mifepristone may interfere with embryo growth by inhibiting the activity of TGF-β or by stimulating the secretion of TNF-α.

0 05). TGF ? expression rate of drug abortion group was similar to that of artificial abortion group. The highly positive (++ and +++) TNF ? expression rate in drug abortion group was significantly higher than that in artificial abortion group ( P