Endometriosis and Implantation

Approximately 60% of women with endometriosis are subfertile, that is, their cumulative pregnancy rates are lower than those of controls.1 Although not yet completely understood, it appears that the detrimental effects of endometriosis on fertility are pleiotropic in nature and include distortion of the pelvic anatomy by the formation of adhesions and biochemical alterations, resulting in a microenvironment that negatively affects folliculogenesis,2-4 fertilization,5 embryogenesis,6 and implantation.7-9 This chapter will address (a) the process of implantation and its frequency in natural and assisted reproductive technology (ART) cycles; (b) the molecular basis for implantation; (c) the effects of endometriosis on implantation; and (d) the potential treatment of implantation defects associated with endometriosis.