Abstract: Objective To study the expression of matrix metalloproteinases (MMPs ) in the decidual stromal cells (DSCs) and extravillous cytotrophoblasts (EVCT) in human early pregnancy and explore the change of MMPs in endometrial stromal cell (ESC) decidualization and its impact on implantation and placentation. Methods The decidua and villi from 5 women with early pregnancy and mid-secretory endometrium from 5 normal women were collected and cultured in vitro, and the supernatants of the culture media were collected after 48 hours of incubation. The expression of the MMPs in the ESCs, DSCs and EVCTs was detected using Luminex xMAP system simultaneously and the difference in MMPs expression and their correlations were analyzed with SPSS10.0 software. Results The MMPs (MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, and MMP-9) were expressed in ESCs, DSCs and EVCTs, while MMP-12 was not found in ESCs and MMP-13 not in DSCs. Expressions of MMP-8, MMP-12, and MMP-13 were lowered. Compared with the ESCs, DSCs and EVCTs showed significantly lowered expressions of MMP-1, MMP-3, and MMP-7 (P<0.05), whereas expression of MMP-2 and MMP-9 increased significantly, and the high expressions of MMP-1, MMP-3, and MMP-7 was especially obvious in the DSCs. The expressions of MMP-1, MMP-3, and MMP-7, however, were significantly decreased in the EVCTs in comparison with the DSCs. Significant correlations were noted between MMP-1, MMP-3, and MMP-7, and MMP-2 was closely correlated with MMP-9. MMP-8 was significantly lower and MMP-12 and MMP-13 showed no obvious variation in the cell culture. Conclusion MMPs are secreted by ESCs, DSCs and EVCTs. Diverse MMPs play an important role in proliferation and differentiation of the ESC to affect embryo implantation and placentation. All MMPs establish a balance to co-regulate the process of pregnancy.