New advances in the understanding of endometriosis related infertility.

The association between endometriosis and infertility is complex. Nevertheless, in the absence of tubal distortion considerable evidence suggests four principle factors likely to contribute to subfertility. These include impaired folliculogenesis, decreased fertilization, inflammatory factors in follicular, peritoneal and reproductive tract fluid, and implantation defects. The potential impact of each of these is critically examined. The role of endometriomas, prior surgeries and donor oocytes is also discussed.