While endometriosis is known to impair fertility, the underlying mechanisms are still not thoroughly understood.
In couples presenting with infertility endometriosis though is not assumed to be the only cause. Subfertility is likely to be partially dependent on the extent of the disease as well as other factors so that couples which present with problems in conceiving undergo a detailed evaluation of contributing factors.
As no medical treatment can improve fertility in endometriosis patients, treatment options are narrowed down to surgical approaches. In women wishing to conceive fertility-sparing surgery of endometriosis should be intended. Removal of endometriotic lesions likely improves the pregnancy rate in mild or moderate endometriosis whereas in severe disease in vitro fertilization (IVF) may be the treatment of choice. In rare cases and on individual basis medical treatment might be discussed prior to fertility treatment.
According to guidelines of the American Society for Reproductive Medicine and the European Society of Human Reproduction and Embryology, ovarian reserve, tubal function (by hysterosalpingography or hysterosalpingo contrast sonography) and partner's semen should be first assessed in infertile women with suspected endometriosis. If all findings are normal and the woman is young, natural conception is possible and expectant management (watchful waiting) or superovulation/intrauterine insemination (SO/IUI) is recommended. Note that the UK National Institute for Health and Care Excellence (NICE) guideline does not recommend the routine use of IUI.
If the patient is of advanced reproductive age, or at least one parameter (ovarian reserve, tubal function and partner's semen) is not normal, she should be scheduled for an assisted reproductive technique (ART) unless she has severe pain, a large endometrioma (that might cause rupture or limit the oocyte retrieval) or suspected malignancy. Endometrioma can be detected and monitored by ultrasonography or MRI.
Laparoscopy should be considered for patients in need of pain relief, cyst removal or histological diagnosis; however, adverse aspects of surgery (such as diminishing ovarian reserve) should be taken into account. Patients who failed to achieve natural conception after expectant management or SO/IUI for >6–12 months are also advised to receive ART. Prolonged hormonal downregulation before ART seems to benefit ART outcomes.
As for all clinical guidelines, individual treatment decisions should always be made based on the patient’s characteristics and desired outcomes.