A 34-year-old woman presents to the fertility clinic with a 2-year history of difficulty conceiving. She reports severe dysmenorrhea and deep dyspareunia, which have progressively worsened over the past five years. Her menstrual cycles are regular, but she describes heavy bleeding lasting 7–8 days. She has no significant medical history but underwent an appendectomy at age 15. She has attempted timed intercourse and lifestyle modifications without success. On physical examination, the patient exhibits tenderness in the lower abdomen and nodularity in the posterior fornix on bimanual examination, suggestive of endometriosis. Which of the following is the primary mechanism by which endometriosis affects fertility?
