Human reproduction is a very complex process and now a days it is not very efficient because of various environmental chemicals, smoking and diet factors affecting the fertility [1 ]. Early pregnancy loss in humans often occurs due to defects before, during or immediately after implantation, is a worldwide social and economic concern. In majority of cases, spontaneous abortion occur at the time of blastocyst implantation due to inappropriate uterine environment results diminished uterine receptivity or delayed implantation [2 ]. This unwanted failure of pregnancy causes emotional and psychological stress in women which emerges another clinical problem-the problem of infertility. Many underlying causes of human infertility have been overcome by in vitro fertilization and embryo transfer technique. The ultimate goal of understanding implantation at a molecular level is to improve the diagnosis and treatment of infertility. Normal fertility involves production and maturation of male and female germ cells by the gonads, fertilization of the oocyte by spermatozoa and implantation in the uterus. The implantation of the healthy blastocyst into the maternal receptive uterus is a very crucial step in mammalian reproduction for successful pregnancy and it involves an intricate succession of genetic and cellular interactions, all of which must be executed within an optimal time frame. The fertilized egg undergoes specific cell divisions to form a blastocyst. These developmental events are synchronized with the proliferation and differentiation of specific uterine cell types, primarily under the direction of ovarian hormone like Progesterone (P4) and Estrogen (E2). These hormones make the uterus conductive (receptive) to accept a blastocyst for implantation. A reciprocal interaction between the blastocyst and receptive uterus is essential for blastocyst implantation.