Randomly selecting 20-40 years patients were prepared to accept frozen embryo transplant ; HRT cycle preparation of endometrium；choosing HRT plan to prepare the transplantation endometrium.Establishing a strict standard of exclusion and exclude standard to exclude endometrial lesions and underlying disease.The patients were given elastography for 5-7 days afterEndometrium transformation.Observing the correlation between endometrial elasticity score, endometrial blood flow index (PI, RI, S/D, endometrial thickness, morphology) and clinical pregnancy rate. In order to find a non-invasive, convenient and comprehensive evaluation method of evaluating the endometrial receptivity, and to provide effective means for the frozen embryo transplantation patients to improving pregnancy outcome.
Prospective clinical study ：observing the correlation between endometrial elasticity score, endometrial blood flow index (PI, RI, S/D, endometrial thickness, morphology) and clinical pregnancy rate. In order to find a non-invasive, convenient and comprehensive evaluation method of evaluating the endometrial receptivity, and to provide effective means for the frozen embryo transplantation patients to improving pregnancy outcome.