After embryo transfer, the embryo must initiate a cascade of communication with the uterine endometrium for implantation to occur and thus initiate embryonic development. Numerous growth factors, hormones and other molecules are involved in this process.
Numerous studies suggest that endometrial curettage improves the likelihood of implantation in patients with repeated IVF failures. However, there is no evidence that this technique is effective across the board, i.e. it is not recommended for other reasons of infertility.