【Objective】 To study the effect of extrogenous soluble human leukocyte antigen-G (sHLA-G)on trophoblast invasion in chronic villi of unexplained recurrent spontaneous abortion and then provide scientific evidence for treatment strategies. 【Methods】 The villi of 8-10 weeks gestation were collected from 50 women

30 cases of normal induced abortion

and 20 cases of unexplained recurrent spontaneous abortion (RSA). Trophoblast cells were primary cultured

1 bottle for each normal case (normal group) and 3 bottles for each RSA case (control group

group 1

group 2). 0.9% NS

0.9% NS

and 0.05%

0.1% ultimate concentration sHLA-G was added to each group respectively

and continued to cultured for 16 hours. The EVCT were collected from suspension cells and stained by CD146 monoclonal antibody. The expression of CD146 was detected by flow cytometry. 【Results】 The rate of CD146+ EVCT in normal pregnant group was (63.29 ± 6.76)%

significantly higher than the control group (10.61 ± 3.34)%

P < 0.01. (2) The rate of CD146+ EVCT was (64.15 ± 9.54)% in group 2 (0.1% sHLA-G intervention)

significantly higher than that of gruop1(0.05% sHLA-G intervention)(30.61 ± 7.52)%

P < 0.01. The rate of CD146+ EVCT in group 1 and group 2 was both higher than the control group

P < 0.01. There was no significant difference between the normal group and group 2. 【Conclusion】 Exogeneous sHLA-G intervention can significantly improve the invasion of trophoblast cells from RSA patients. It may be one of the effective treatment strategies for RSA.