Spontaneous Ovulation in Patients with Endometriosis

Approximately 20 years ago, studies performed in the animal model of endometriosis suggested that endometrial autografts placed throughout the pelvic peritoneum caused infertility by interfering with ovulation. Based on this background, some studies investigated if ovarian endometrioma influenced the frequency of ovulation in the affected ovary. Initial studies suggested that ovulation occurs less frequently in ovaries with endometriomas. However, more recently, a prospective Italian study including 244 women with unilateral endometriomas demonstrated that ovulation is not affected by the presence of endometrioma and that the number and the size of endometriomas do not influence ovulation. Endometriosis may impair fertility through multiple pathways, including peritoneal inflammation, endocrine derangements that reduce oocyte competence, and decreased endometrial receptivity; however, it does not seem to affect spontaneous ovulation significantly.