着床是胚泡植入子宫内膜的过程。正常子宫内膜仅在一特定时期允许着床,这一时期子宫内膜容受性最高,称为“着床窗”期。着床窗期一般为排卵后6～10d,即正常月经周期的20～24d。尽管辅助生殖技术已取得一些进步,但着床缺乏控制仍是获得成功妊娠的一个主要障碍,因此明确子宫内膜 Implantation is the process of blastocyst implantation in the endometrium. Normal endometrium only permits implantation at a specific time, during which endometrial receptivity is highest, referred to as the “implantation window” period. Implantation window is generally 6 ~ 10d after ovulation, that is, the normal menstrual cycle 20 ~ 24d. Although some advances have been made in assisted reproductive technology, lack of control of implantation is still a major obstacle to a successful pregnancy and it is therefore clear that endometrial