ABSTRACT
Recent advances in our understanding of ovarian stimulation, the techniques of oocyte retrieval, the handling of gametes, the methods of assisted fertilisation and improved conditions of culture medium have steadily increased the fertilisation rate, but implantation failure following embryo transfer still remains a major disappointment. For successful implantation, synchronization of the embryo development and uterine prepation is necessary
Embryo implantation is a highly controlled physiological process, involving complex interactions between the implanting embryo and the maternal endometrium.1 Overall, responsibility for co-ordination of implantation lies with the ovarian hormones oestrogen and progesterone. However, it is now clear that, locally acting soluble factors secreted by the endometrium can act on the embryos to influence it’s development. Developing embryos in turn have been shown to produce soluble factors that can act in an autocrine manner or on the endometrium to influence the receptivity.
