Stages of Endometriosis

Key Takeaways

• Endometriosis affects 1 in 10 women of childbearing age worldwide, making it a common recurring condition. It occurs when the body produces endometrial tissue in places outside the uterus, where it doesn't belong, and can’t eliminate it. 
• Left untreated, endometriosis can become painful and lead to serious side effects including inflammation, scar tissue, pain during sex and urination, and infertility.
• Estimates suggest that up to 30% to 50% of women with endometriosis may find it harder to get pregnant. 
• Treatments can relieve symptoms and address infertility that can result, although there is no known cure for endometriosis. 

What Is Endometriosis

Endometriosis is a common disease that affects nearly 200 million women and girls around the world. The World Health Organization estimates this figure represents 10% of females globally who are of childbearing age.  So what is endometriosis? During a normal menstrual cycle, the tissue that forms the lining of the uterus (endometrium) thickens to help support a pregnancy.

This is a dramatic process where the inside of the uterus thickens to 1 cm in about a week. This represents truly explosive cellular growth. Think of this as the equivalent of growing a mass the size of a tongue in one week. Practically nothing else in the human body grows as rapidly as endometrial cells. This is great for establishing a place where a pregnancy can thrive – but what happens if these cells grow someplace they are not supposed to be?

Every month when there is a menstrual period, these endometrial cells are expelled from the uterus and out of the vagina, but not ALL of those cells make it out through the vagina. In the vast majority of women, these endometrial cells make their way through the fallopian tubes into the abdomen. The immune system is programmed to kill these cells, and the endometrial cells themselves are programmed to die outside of the uterus. Endometriosis occurs when all of these cells do not die outside of the uterus.

When they don’t die, they do what they are programmed to do inside the uterus: experience explosive growth in response to hormones. The immune system typically fights this invasion of endometrial cells in the abdomen violently, causing significant pain and inflammation. Given enough time, this even leads to scarring and destruction of other surrounding structures. When endometriosis is aggressive enough, the endometrial cells can themselves invade inside other surrounding organs like the uterus and ovaries and cause damage from the inside out of these organs.  

What's even more puzzling is that while the severity of endometriosis tends to correlate with symptoms, there are many exceptions. So the apparent severity of endometriosis may not necessarily correlate with pain, infertility, or other classic symptoms. Therefore, women with “mild” clinical endometriosis may still experience pain or infertility, while others with more “severe” clinical presentations may not. 

Types of Endometriosis

At its core, endometriosis is any growth of endometrial cells outside of where they are supposed to live in the uterus. 

Doctors have developed certain terms to classify where the endometriosis is growing – but at the end of the day, these are just terms used to describe severity and location, not fundamental differences in the disease.

Several terms you may hear in regards to endometriosis include:

• Superficial Ovarian and Peritoneal Growth: This is the most common form of endometriosis, estimated to make up nearly 80% of all cases. This type of endometriosis forms on the surface of organs, such as the bladder, intestines, reproductive system, or even the membrane lining the abdominal cavity, called the peritoneum.
• Deep Infiltrating Endometriosis (DIE): Think of DIE as a more advanced, more invasive form of superficial endometriosis. This is when the superficial endometriosis invades deeper into the tissue where it’s growing. This causes more severe scarring and can even destroy nerves, leading to pain that is difficult to control. It’s estimated to impact only about 1% of women of childbearing age. 
• Endometriomas: Known as “chocolate cysts,” endometriomas occur when endometrial cells actually invade INSIDE the ovary. Once there, the endometrial cells grow and form a cyst with a lining that actually resembles the inside of the uterus. Therefore, whenever there is a menstrual cycle, these endometrial cells also grow and bleed – over time leading to large collections of blood within the ovaries themselves. This old blood is dark in color and appears brown, leading to the name “chocolate cysts.” These cysts cause inflammation within the ovary and can compromise function. Management of these cysts depends on a host of variables.
• Adenomyosis: Adenomyosis occurs when the endometrial cells invade into the muscle wall of the uterus itself. This is particularly problematic, as the scarring that is caused from the inflammatory response to these cells may cause significant compromise to blood flow during a pregnancy. Compounding this, surgical correction is difficult as margins to remove this tissue are difficult to define and healing may be poor due to compromised blood supply. Thankfully, recently developed IVF protocols provide a path to minimizing the impact of adenomyosis on women wishing to conceive. 

Stages of Endometriosis

In determining how to classify endometriosis, doctors have come up with various staging systems to help describe endometriosis. Perhaps the most well known system uses a “1-4” system with classifications for each score. Other practitioners simply describe the endometriosis observed by describing the location and depth of invasion of the various endometriosis lesions. Still others simply classify it as mild, moderate, or severe. In most staging systems however, infiltrative organ involvement such as endometriomas or adenomyosis defaults to the most severe ranking stage.

However, as previously mentioned, the observed severity of endometriosis is not always correlated with the severity of symptoms. Some individuals with lower-stage endometriosis may experience severe symptoms, while others with advanced-stage endometriosis may have minimal symptoms. Therefore, understanding the severity of symptoms and their impact on a patient’s comfort is most important for personalized management and treatment decisions.

Endometriosis and Fertility

Getting pregnant is frequently more difficult for those who have endometriosis, especially when symptoms are more severe. Not everyone will experience fertility issues, but it is a relatively common complication of the condition. In fact, one study found that up to 30% to 50% of women with endometriosis may experience infertility. Endometriosis can affect fertility in numerous ways, including: 

• Pelvic anatomy changes
• Adhesions (sticky bands that can form between organs)
• Fallopian tube scarring
• Pelvic inflammation
• Immune system changes
• Hormonal environment shifts
• Pregnancy implantation challenges
• Changes in egg quality

Endometriosis and Treatment

At its core, endometriosis is the failure of the body to eliminate endometrial cells that are outside the uterus. Because this is a result of how the body functions, there is not a “cure” for endometriosis – much the same way other diseases that are caused by autoimmune dysfunction such as rheumatoid arthritis have no cure. 

Comparing Endometriosis to Grass

Think of endometrial cells as a lawn with tall grass. You can cut the lawn and reduce its bulk, but it will eventually grow back. Similarly, surgery can help decrease endometriosis but not eliminate it.

Continuing the grass comparison, you could cut off the grass’s water supply, causing the grass to become brown and stop growing. That’s how most medical therapies work for treating endometriosis – they’re aimed at limiting the amount of “unopposed estrogen” to which endometrial cells are exposed. This includes a host of therapies inducing birth control pills, progesterone releasing IUDs, and other medications like Orilessa and Lupron. However, just like the lawn, when these medical therapies are stopped, the grass will green up and start growing again. Also, it is challenging to obtain a pregnancy with these therapies, since they are generally aimed at stopping ovulation.

You could let the grass grow normally with plenty of water. This would be similar to continuing to have cycles naturally while attempting pregnancy. Every month, the endometrial cells would be exposed to estrogen and continue to grow and bleed – causing ever-worsening inflammation and anatomic damage. 

Finally, you could remove the grass by removing the sod altogether. This would be the equivalent of a hysterectomy – removing the source problem. However, this option is obviously not acceptable to most women desiring fertility.

In Vitro Fertilization (IVF)

Thankfully, In Vitro Fertilization (IVF) is an option that has emerged as the gold standard for treating many difficult endometriosis cases. By extracting the eggs directly out of the ovaries, the impact of the inflammatory endometriosis environment on eggs is minimized. Embryos can be grown in a laboratory, far away from this inflammatory environment. And when it is time for implantation into the uterus, medical suppression can be highly effective in creating the best possible conditions for an early pregnancy. So while IVF can’t cure endometriosis, it has emerged as our best tool to combat this disease when trying to get pregnant. 

When to Consult a Fertility Care Expert

If you’ve been actively trying to conceive for one year without success, it’s recommended to consult a fertility specialist. For women over 35, seeking help after six months of trying is advisable. Early intervention can lead to better outcomes since fertility generally declines with age.Furthermore, if you have experienced issues such as irregular periods, pelvic pain, or suspect you may have endometriosis, consider seeing a specialist sooner.

These conditions can impact fertility and require expert evaluation.Our board certified reproductive endocrinologists at SDFC specialize in treating various stages of endometriosis and fertility. They can assess your unique situation, provide personalized guidance, and develop a treatment plan tailored to your needs. Contact our office to schedule your appointment. 

This article is for informational purposes only and is not intended to represent medical advice. Please consult with a fertility care expert for personalized recommendations.