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How Endometriosis Contributes to Infertility

How endometriosis impairs fertility—mechanisms, pathways, and treatments.

By Dr Steven Vasilev
Top-down flat vector of a fertility lab bench showing endometriosis mechanisms—adhesions, inflammation, endometriomas, and reduced egg reserve—linked to treatments like excision surgery, IVF/ICSI, and hormonal suppression.

Endometriosis and Fertility: Essential Insights


Endometriosis is a complex and often misunderstood condition that can substantially affect fertility. Gaining clarity on how it develops, why it occurs, and the ways it can influence conception is important for identifying effective treatment strategies.


What Is Endometriosis?


Endometriosis is a benign, estrogen-dependent disorder that affects approximately one in ten cisgender women during their reproductive years. It may also affect transgender men, where the condition may be present at a higher percentage. Although cases have been reported in cisgender men, they are exceedingly rare. The discussion of fertility here focuses on impacts involving the uterus, Fallopian tubes, and ovaries.


The condition is defined by the presence of endometrial-like tissue outside the uterus. These implants are often located within the pelvis—on the ovaries, fallopian tubes, and the outer surface of the uterus—though in some instances they extend beyond the pelvic region. While an estimated 10–15% of cisgender women of reproductive age are affected, endometriosis is even more prevalent among those facing infertility, occurring in up to 25%–50% of this group. The underlying cause remains under investigation, and its impact on fertility is multifactorial and complex.


How Endometriosis Develops: Leading Theories


Multiple theories aim to explain the pathogenesis of endometriosis, reflecting the complexity of the condition and its varied presentation.


Retrograde Menstruation


The oldest and most widely known theory suggests that menstrual blood containing endometrial cells flows backward through the fallopian tubes into the pelvic cavity. These cells then attach to peritoneal surfaces, proliferate, and form endometriosis implants.


Coelomic Metaplasia and Metastatic Spread


Another perspective posits that cells in the peritoneum can transform into endometrial cells, a process called coelomic metaplasia. A separate but related hypothesis proposes that endometrial tissue spreads via the bloodstream or lymphatic system to distant sites, accounting for implants found outside the pelvis.


Altered Immunity


A further theory proposes that individuals with endometriosis may have immune system alterations that fail to clear endometrial cells from the peritoneal cavity. This immune dysfunction may also facilitate disease progression by promoting the survival and growth of implants.


Stem Cells and Genetics


Emerging research points to the involvement of stem cells and genetic predisposition. Bone marrow–derived stem cells may differentiate into endometriosis cells, contributing to ectopic endometrial-like tissue. Genetics also appear to play a substantial role, with a first-degree relative affected by the disease increasing a person’s risk by sevenfold.


Learn more: Current Knowledge on Endometriosis Etiology: A Systematic Review


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How Endometriosis Can Cause Infertility


Endometriosis can impair fertility through several mechanisms that affect gametes, embryo transport, and implantation.


Effect on Gametes and Embryo


Endometriosis may influence the production and quality of oocytes and can also affect sperm function and embryo health. Endometriomas and the inflammatory environment they create can negatively affect oocyte production and ovulation.


Effect on Fallopian Tubes and Embryo Transport


Inflammation associated with endometriosis can disrupt fallopian tube function and normal uterine contractions. These changes can impair tubal motility and hinder the transport of eggs, sperm, and embryos.


Effect on the Endometrium


Endometriosis can alter the uterine lining, potentially leading to implantation failure. Research indicates that changes in gene expression within the endometrium may reduce its receptivity to embryo implantation.


Treatment Options for Endometriosis-Associated Infertility


Approaches to managing infertility related to endometriosis include expectant management, medical therapy, surgical intervention, and assisted reproductive technologies, with the goal of improving reproductive outcomes based on disease severity and individual circumstances.


Expectant Management


Some individuals with mild to moderate endometriosis may conceive without intervention, particularly younger patients without additional fertility problems. Despite the overall reduction in fertility rates associated with endometriosis, careful observation can be an appropriate option in selected cases.


Surgical Treatment


Surgery can serve both diagnostic and therapeutic purposes. The primary aims are to remove or reduce endometriosis implants, restore normal pelvic anatomy, and lessen inflammatory effects. These outcomes may improve fertility, especially in those with more severe disease.


Assisted Reproductive Technology


In vitro fertilization (IVF) is currently the most effective treatment for infertility associated with endometriosis. It is particularly beneficial for individuals with severe endometriosis or for those who have not achieved pregnancy with other treatments.


Medical Treatment


Hormonal medications—including combined oral contraceptives, progestins, danazol, and gonadotropin-releasing hormone agonists or antagonists (GnRH analogs)—are commonly used to reduce disease severity and alleviate symptoms. However, these therapies have not demonstrated significant benefit in treating endometriosis-associated infertility itself.


The Road Ahead: Potential Future Treatments


As research advances, novel therapies targeting abnormal gene expression and inflammatory pathways are being explored. Stem cell–based approaches and genetic interventions also hold promise for addressing endometriosis-associated infertility. Continued scientific progress offers hope for more effective strategies to manage this condition and improve fertility outcomes.

References

  1. Macer ML, Taylor HS. Endometriosis and infertility: a review of the pathogenesis and treatment of endometriosis-associated infertility. Obstet Gynecol Clin North Am. 2012 Dec;39(4):535-49. doi: 10.1016/j.ogc.2012.10.002. PMID: 23182559; PMCID: PMC3538128.

Quick Answers

How rare is endosalpingiosis?

Endosalpingiosis is generally considered uncommon, but “how rare” it is depends heavily on who’s being studied and how it’s found. Many cases are discovered incidentally on pathology—meaning tissue is identified under the microscope after surgery done for other reasons—so it’s likely underrecognized in the general population. In other settings (like surgical cohorts), it may appear more often simply because more tissue is being sampled and examined carefully.


What matters most for patients is that endosalpingiosis can be confused with endometriosis on imaging or even at surgery, yet it doesn’t always behave the same way clinically. If you’ve been told you have endosalpingiosis and you also have pelvic pain, bowel/bladder symptoms, or fertility concerns, our team can help interpret what that finding means in the context of your symptoms and operative/pathology reports. You’re welcome to explore our educational content on related endometriosis and uterine conditions, and reach out to schedule a consultation if you want a personalized plan.

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What is pelvic dissection in endometriosis surgery?

Pelvic dissection in endometriosis surgery means carefully separating and opening tissue planes in the pelvis so we can clearly see normal anatomy and remove disease safely. Endometriosis can cause inflammation and scarring that “glues” organs together (sometimes called a frozen pelvis), so dissection is often the step where we free adhesions and restore normal relationships between the uterus, ovaries, bowel, bladder, and pelvic sidewalls.


In practical terms, pelvic dissection may include identifying and protecting critical structures like the ureters, bladder, bowel, blood vessels, and pelvic nerves before excising endometriosis at its roots. This is where surgical precision matters: the goal is to fully address disease while minimizing injury to healthy tissue, especially in complex or re-operative cases. If you’re seeing this term on an op note or surgical plan, it usually reflects the complexity of the anatomy and the deliberate work needed to make excision both complete and safe—our team can walk you through exactly what was dissected and why in your specific case.

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How does estrogen affect the endometrium?

Estrogen is one of the main hormones that drives endometrial growth. In the first half of the menstrual cycle, rising estrogen signals the endometrium to thicken and rebuild after a period, preparing the uterus for a possible pregnancy. It also influences the local immune and inflammatory environment in the uterus, which is part of why hormonal shifts can change bleeding patterns and pain.


When estrogen’s growth signals are strong—and progesterone’s “calming” effect is weaker than expected (often described as progesterone resistance)—the endometrium can behave in a more persistently inflamed, reactive way. This hormone–inflammation pattern is especially relevant in estrogen-dependent conditions like adenomyosis and endometriosis, where tissue similar to the endometrium can contribute to ongoing symptoms. If you’re trying to make sense of heavy bleeding, severe cramping, or cycle-linked pelvic pain, our team can help you connect the hormonal biology to what you’re feeling and review next steps for diagnosis and treatment.

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What does a frozen uterus mean with endometriosis?

A “frozen uterus” isn’t a separate diagnosis—it’s a descriptive term surgeons use when the uterus is essentially stuck in place because endometriosis-related inflammation has caused dense scarring (adhesions). Instead of the uterus moving freely, it may be tethered to nearby structures like the bowel, bladder, ovaries, or pelvic sidewall, sometimes pulling the uterus into an abnormal position and making pelvic anatomy hard to distinguish.


This finding often suggests more advanced disease, such as deep infiltrating endometriosis and/or significant adhesions from prior inflammation or surgery, and it can help explain symptoms like deep pelvic pain, painful sex, bowel or bladder symptoms, or pain that doesn’t match what a routine exam shows. In these cases, surgery is less about “burning spots” and more about carefully restoring normal anatomy—freeing organs, protecting ureters and bowel, and removing endometriosis at its roots. If you’ve been told your uterus is “frozen,” our team can help you understand what that implies for imaging, surgical planning, and which adjacent organs may need to be evaluated as part of a complete excision strategy.

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What are peritoneal pockets in endometriosis?

Peritoneal pockets are small “indentations” or fold-like defects in the peritoneum—the thin lining that covers the pelvic organs and inner abdominal wall. In endometriosis surgery, we may see these pockets as tucked-in areas or little pits in the peritoneal surface, and they can be associated with superficial peritoneal endometriosis or early/developing disease patterns.


These pockets matter because endometriosis doesn’t always look like obvious black or red implants; it can hide within subtle anatomic changes, scarring, or altered peritoneal contours. In the operating room, careful inspection and technique are important so that disease within or around a peritoneal pocket isn’t missed or only treated on the surface. If you’ve been told you have “peritoneal pockets,” our team can help you understand what that finding may mean in your case—based on your symptoms, imaging, and whether deeper structures (like bowel, bladder, or ureters) could also be involved.

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Have a question?

Dr. Steven Vasilev delivers best-in-class endometriosis guidance and a personalized treatment plan—built on evidence and your unique biology.


Led by Steven Vasilev, MD—an internationally recognized endometriosis specialist & MIGS surgeon—Lotus Endometriosis Institute is virtual-forward, with many patients traveling nationally for care. Clinical evaluation and surgical treatment are provided in California.

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