Endometriosis contributes to infertility through which mechanisms?

• A. Adhesions and distortion
• B. Inflammatory peritoneal environment
• C. Impaired tubal function
• D. All of the above

Answer: (D)

Endometriosis lowers fertility through several interrelated pathways that affect pelvic anatomy, the peritoneal environment, and tubal function. Adhesions and distortion occur as endometriotic scars form in the pelvis, pulling on and fixing the uterus, ovaries, and especially the fimbrial end of the fallopian tubes. This mechanical alteration can hinder ovum pickup, disrupt tubal patency, and change the normal alignment needed for fertilization. The inflammatory peritoneal environment is a hallmark of endometriosis, with elevated cytokines, prostaglandins, and immune mediators in the peritoneal fluid. This inflammatory milieu can impair ovulation, oocyte quality, fertilization, embryo development, and implantation, and it can also affect sperm function in the peritoneal cavity. Impaired tubal function arises from both the mechanical distortion and the inflammatory effects, including reduced ciliary movement and slower transport of gametes and embryos through the tubes. Because these mechanisms can act together, endometriosis commonly reduces fertility via all these routes, making the combined effect the best explanation.