Endometriosis, a complex and often misunderstood condition, can significantly impact a woman’s fertility. Understanding the intricacies of this condition, its causes, and its effects on fertility can be vital in paving the way for effective treatment strategies.
An Introduction to Endometriosis
Endometriosis is a benign, estrogen-dependent disorder primarily affecting approximately one in ten cisgender women in their reproductive years. It may also have an impact on transgender men, where the condition may be present in a higher percentage. While it has been reported in cisgender men, it is exceedingly rare. Thus the fertility impact discussed here is that which specifically affects the uterus, Fallopian tubes and ovaries.
Endometriosis is characterized by the abnormal presence of endometrial-like tissue outside the uterus. This abnormally growing tissue is often found in the pelvic region, such as on the ovaries, fallopian tubes, and the outer surface of the uterus. Still, in some cases, it can extend beyond the pelvic area.
While endometriosis affects approximately 10-15% of cisgender women in their reproductive years, the condition is more prevalent in those struggling with infertility, affecting up to 25%-50% of this demographic. The exact cause of endometriosis remains a subject of research and debate, and its impact on fertility is multi-faceted and complex.
Understanding The Pathogenesis of Endometriosis
While the precise cause of endometriosis is still under debate, several theories have emerged over the years, trying to explain the pathogenesis of this condition.
Retrograde Menstruation
The oldest theory is retrograde menstruation, which suggests that during menstruation, some of the endometrial tissue flows backward, through the fallopian tubes, into the pelvic cavity instead of leaving the body. These endometrial cells then attach to the peritoneal surfaces, proliferate, and form endometriosis implants.
Coelomic Metaplasia and Metastatic Spread
Other theories suggest that cells in the peritoneum can transform into endometrial cells, a process known as coelomic metaplasia. Alternatively, endometrial tissue may spread through the bloodstream or lymphatic system to other parts of the body, a process known as metastatic spread. Both these theories could explain how endometriosis implants can be found in areas outside the pelvic region.
Altered Immunity
Another theory proposes that women with endometriosis have a compromised immune system, which fails to eliminate the endometrial cells that have migrated to the peritoneal cavity. This immune dysfunction may also contribute to the progression of the disease, as the immune system’s reactions may inadvertently promote the growth and proliferation of endometrial implants.
Stem Cells and Genetics
Recent research also suggests that stem cells and genetic factors may play a role in the development of endometriosis. Bone marrow-derived stem cells may differentiate into endometriosis cells, contributing to the formation of ectopic endometrial-like tissue.
Additionally, genetic predisposition may play a significant role in the development of endometriosis. People with a first-degree relative affected by the disease have a seven times higher risk of developing endometriosis.
Learn More: Current Knowledge on Endometriosis Etiology: A Systematic Review
How Does Endometriosis Cause Infertility?
Endometriosis can affect fertility through various mechanisms:
Effect on Gametes and Embryo
Endometriosis can impact the production and quality of oocytes (eggs), as well as sperm function and embryo health. The presence of endometriomas (cysts caused by endometriosis) and the inflammatory environment they create can negatively affect both oocyte production and ovulation.
Effect on Fallopian Tubes and Embryo Transport
Endometriosis can disrupt the fallopian tubes’ normal functioning and impact the embryo’s transport. The inflammation caused by endometriosis can impair tubal motility and cause abnormal uterine contractions, which can hinder the transportation of gametes (eggs and sperm) and embryos.
Effect on the Endometrium
Endometriosis can also impact the uterine lining or endometrium, which can lead to implantation failure. Research suggests that endometriosis can alter the gene expression in the endometrium, affecting its receptivity to implantation.
Read More: Learn More About the Connections Between Endometriosis and Infertility
Current Treatment Options for Endometriosis-Associated Infertility
The treatment of endometriosis-associated infertility is multi-faceted and can include expectant management, medical treatment, surgical treatment, and assisted reproductive technologies.
Expectant Management
While endometriosis significantly lowers fertility rates, some women with mild to moderate endometriosis can still conceive without any medical or surgical intervention. However, this approach may be more suitable for younger women with mild endometriosis and no other fertility issues.
Surgical Treatment
Surgery can be both diagnostic and therapeutic in the context of endometriosis. The goal of surgical treatment is to remove or reduce endometriosis implants and restore normal pelvic anatomy and reduce the inflammatory impact. This could potentially improve fertility, particularly in women with severe endometriosis.
Assisted Reproductive Technology
In vitro fertilization (IVF) is currently the most effective treatment for endometriosis-associated infertility. IVF can be particularly beneficial for women with severe endometriosis or those for whom other treatments have failed.
Medical Treatment
Medical treatment for endometriosis primarily targets reducing the severity of the disease and relieving symptoms. Hormonal medications such as combined oral contraceptives, progestins, danazol, and gonadotropin-releasing hormone agonists or antagonists (GnRH analogs) are commonly used. However, these medications have not shown any significant benefit in treating endometriosis-associated infertility.
Read More: Natural, Medical & Surgical Treatment of Endometriosis Infertility
Looking Towards The Future: Potential Treatments
As our understanding of endometriosis deepens, new potential treatment options are emerging, such as therapies targeting the abnormal gene expression and inflammation caused by endometriosis. Furthermore, stem cell therapies and genetic interventions hold promise for treating endometriosis-associated infertility in the future. As research continues, the hope is that these advancements will lead to more effective strategies for managing this complex condition and improving fertility outcomes in those with endometriosis.
Read More: How Do Endo Fertility Issues Impact the Mental Health of a Person?
Reference: Macer ML, Taylor HS, Obstet Gynecol Clin North Am. 2012 Dec;39(4):535-49.
