The Different Stages of Endometriosis Explained

Endometriosis is a common medical condition in which tissue similar to the lining of the uterus (endometrium) escapes and implants on structures outside of the uterus. These lesions can grow anywhere. Generally they stay in the pelvic area and implant behind the uterus and on the ovaries and fallopian tubes.

Famously misunderstood and misdiagnosed, endometriosis is a mysterious condition with more questions than answers.

How does endometrial tissue leave the uterus?

How can I prevent the condition and lower my risk?

Why does someone with only a few lesions have severe symptoms while someone with a lot of lesions experience little pain?

But here's what we do know. During your menstrual cycle, just like the lining of the uterus, endometriosis lesions located outside of the uterus thicken and shed. Except it has no way of leaving the body. This process can lead to inflammation, scar tissue, cysts, pain, and infertility.

People with endometriosis know something about the condition too: It can often take years to diagnose and treat. In the meantime, the condition can significantly impact a person’s quality of life.

Healthcare providers widely use the classification system created by the American Society of Reproductive Medicine. It’s nearly impossible to quantify endometriosis, but understanding the various stages of this condition can be important for managing expectations and considering treatment options. This article aims to explain the four stages of endometriosis while also demystifying the condition and offering support for the journey ahead.

The Four Stages of Endometriosis

Staging endometriosis is based on several factors, including the number, size, and location of lesions as well as how deep they are in the tissue. It’s also important to keep in mind that this classification system was created to predict fertility and not severity of pain or other symptoms.

Unfortunately, even with an uptick in understanding about endometriosis, studies still show the extent of endometriosis doesn’t correlate to severity of symptoms. This means someone with stage 1 or minimal endometriosis may experience more pain and symptoms than a person with stage 3 or moderate endometriosis.

Stage 1: Minimal

In stage 1 endometriosis or minimal endometriosis, lesions are typically small and shallow. Since these implants are superficial (closer to the surface of tissue), there may not be any scar tissue and symptoms can be light. For these reasons, it’s not uncommon for stage 1 endometriosis, which is also called superficial peritoneal endometriosis, to go undiagnosed.

Stage 2: Mild

Stage 2 endometriosis or mild endometriosis involves a greater number of lesions and deeper implants than stage 1. These implants may still be small but are more widespread. Also, while scar tissue might be present, there usually isn’t inflammation. During this stage, symptoms may become more noticeable and can include pelvic pain, especially during menstruation and possibly during sexual intercourse.

Stage 3: Moderate

Stage 3 endometriosis or moderate endometriosis is characterized by multiple deep implants. There can also be endometrial cysts in at least one ovary, which are called endometriomas or chocolate cysts. These cysts develop when tissue implants on the ovary and sheds, leaving behind old, brown blood which collects and grows within a capsule.

Another finding in moderate endometriosis are bands of scar tissue or adhesions that can cause organs to stick together. The symptoms associated with this stage (intense pain, heavy menstrual bleeding) can be more pronounced and might also impact fertility.

Stage 4: Severe

Stage 4 endometriosis or severe endometriosis is the most advanced form of the disease and involves extensive deep implants, large ovarian endometriomas, and significant adhesions. The severe stage of endometriosis can affect multiple organs within the pelvis and beyond and cause widespread pain and problems with bowel movements, urination, intercourse, and fertility.

Everyone is different

Endometriosis varies greatly from person to person and so does the journey to find relief. Living with this condition can be challenging, but with the right support and treatment plan, many people find ways to manage their symptoms.

For people with pelvic pain and other symptoms that suggest endometriosis (stages 1 and 2), first-line treatment usually involves non-steroidal anti-inflammatory drugs (ibuprofen, naproxen) and hormonal birth control methods. 

In moderate and severe cases (stages 3 and 4), advanced hormonal therapies, GnRH agonists, and surgical options, like laparoscopy, might be recommended.

While an experienced healthcare practitioner can make a diagnosis of “clinically suspected” endometriosis and work with you to devise and revise a treatment plan, in reality laparoscopic surgery is the only definitive way to diagnose (and stage) the condition. During this minimally invasive procedure, which is both diagnostic and curative, a surgeon uses a small camera to locate endometriosis and then removes adhesions and lesions in an effort to reduce pain and improve fertility.

Even if endometriosis is complicated and full of questions, there are answers out there. Growing awareness and advancements in medical research hold real promise for improved management and outcomes for people suffering with this condition. So, keep the faith, and most importantly, keep the communication with your healthcare providers open and honest. Whether you’ve been diagnosed with minimal endometriosis or a more severe form, there are treatments out there and there is a way to reduce symptoms and reclaim your health and wellbeing once and for all.