MMP2 and cytomegalovirus infection: In our study, villous immunohistochemistry staining shows that MMP-2 and MMP-9 protein express largely in early pregnancy villous EVT endochylema, while MMP-9 protein also expresses in high level in early pregnancy villous interstitial substance and VT endochylema; HCMV infection results that villous MMP-2 and MMP-9 expression level both significantly decrease.