What Is Endometriosis? A Complete Guide to Symptoms, Treatment, and Fertility

Endometriosis affects an estimated 10% of women of reproductive age worldwide — roughly 190 million people — making it one of the most common gynecological conditions on the planet. Yet it remains one of the most misunderstood, with an average diagnostic delay of 4 to 12 years between the first symptoms and a confirmed diagnosis.

Endometriosis is a chronic condition where tissue similar to the lining of the uterus grows outside the uterus, causing pain, inflammation, and sometimes infertility. There is no cure, but symptoms can be managed effectively with the right combination of medical, surgical, and lifestyle approaches. Here’s what you need to know.

What is endometriosis, exactly?

Endometriosis is a chronic inflammatory disease in which endometrium-like tissue grows outside the uterine cavity. These misplaced cells respond to monthly hormonal cycles just like the uterine lining: they thicken, break down, and bleed. However, because the discarded tissue has no way to leave the body, it triggers inflammation, scarring, and the formation of adhesions that can fuse pelvic organs together.

Common locations for these growths include the ovaries, fallopian tubes, the outer surface of the uterus, the lining of the pelvis, the bowel, and the bladder. In rare cases, lesions appear in distant sites such as the lungs, diaphragm, or even the brain.

According to the World Health Organization, this disease can affect anyone who menstruates, from menarche through menopause, regardless of ethnic origin or social background.

What are the main symptoms of endometriosis?

Symptoms vary dramatically from one woman to another, and severity does not always match the extent of the disease. Some women with severe lesions report little pain, while others with minimal tissue spread experience debilitating symptoms.

The most common signs include:

• Severe menstrual pain (dysmenorrhea) that interferes with daily life
• Chronic pelvic pain that persists outside the menstrual cycle
• Pain during or after sex (dyspareunia)
• Heavy menstrual bleeding or bleeding between periods
• Painful bowel movements or urination, especially during periods
• Bloating, nausea, or diarrhea linked to the menstrual cycle
• Chronic fatigue, often disabling
• Difficulty conceiving
• Anxiety and depression linked to chronic pain

Some women have no symptoms at all and only discover they have endometriosis when investigating infertility or undergoing surgery for unrelated reasons.

How is endometriosis diagnosed?

Diagnosing endometriosis is notoriously difficult. The current global average diagnostic delay is between 4 and 12 years, partly because period pain is widely normalized and partly because symptoms overlap with other conditions like irritable bowel syndrome, pelvic inflammatory disease, and ovarian cysts.

The diagnostic pathway typically follows three steps:

1. Detailed clinical history covering pain patterns, cycle regularity, and symptom severity
2. Pelvic exam and imaging — transvaginal ultrasound or MRI to detect cysts, deep lesions, or adhesions
3. Laparoscopy — a minimally invasive surgical procedure considered the gold standard for definitive diagnosis

Laparoscopy involves inserting a thin camera through a small abdominal incision to visualize and biopsy suspicious tissue. However, modern guidelines increasingly recognize that a clinical diagnosis based on symptoms and imaging is often sufficient to begin treatment, sparing women unnecessary surgery.

What are the stages of endometriosis?

The American Society for Reproductive Medicine classifies endometriosis into four stages based on the extent of lesions, depth of tissue involvement, and presence of adhesions:

Stage	Severity	Typical findings
Stage 1	Minimal	Few superficial lesions, no significant adhesions
Stage 2	Mild	More lesions, slightly deeper, minimal adhesions
Stage 3	Moderate	Numerous deep lesions, small endometriomas, some adhesions
Stage 4	Severe	Many deep lesions, large endometriomas, dense adhesions, organ involvement

Importantly, stage does not predict pain or fertility outcomes. A woman with stage 1 endometriosis may experience worse symptoms than someone with stage 4 disease.

What causes endometriosis?

The exact cause of endometriosis remains unknown, but research has narrowed the field to several plausible mechanisms.

Retrograde menstruation is the oldest theory: menstrual blood flows backward through the fallopian tubes into the pelvic cavity, depositing endometrial cells that implant and grow. This explanation alone is incomplete because retrograde menstruation occurs in most women, while only some develop lesions.

Immune system dysregulation is increasingly recognized as central. Women with endometriosis show higher rates of autoimmune conditions such as lupus, multiple sclerosis, and inflammatory bowel disease, suggesting a faulty immune response that fails to clear misplaced cells.

Genetic predisposition is well documented. Having a first-degree relative with endometriosis raises your risk significantly. Other recognized risk factors include early menarche, short menstrual cycles, heavy bleeding, and never having given birth.

How is endometriosis treated?

There is no cure, but a wide range of treatments can effectively manage symptoms. The right approach depends on symptom severity, age, and fertility goals.

Pain management

First-line options include nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen. For more severe pain, prescription medications and multidisciplinary pain management approaches — including pelvic floor physiotherapy and cognitive behavioral therapy — can substantially improve quality of life.

Hormonal therapy

Hormonal treatments aim to suppress menstruation and slow the growth of endometriotic tissue:

• Combined hormonal contraceptives (pill, patch, ring) — first-line for many women
• Progestins — including the hormonal IUD and oral progestin-only pills
• GnRH agonists and antagonists — induce a temporary medical menopause
• Aromatase inhibitors — reserved for cases unresponsive to first-line hormonal therapy

Surgery

Laparoscopic surgery to remove or destroy endometriotic lesions is recommended for severe pain, large endometriomas, or fertility issues. According to the American College of Obstetricians and Gynecologists, up to 8 in 10 women experience pain again within 2 years of surgery, especially in advanced cases. Hysterectomy with removal of the ovaries is reserved as a last-resort option for women who do not respond to other treatments and are not planning to have children.

How does endometriosis affect fertility?

Endometriosis is one of the leading causes of female infertility. Among women struggling to conceive, 25 to 50% have endometriosis — and roughly one third of women with the condition experience fertility difficulties.

Several mechanisms contribute to reduced fertility:

• Anatomical distortion of the pelvis from adhesions and scarring
• Blocked or damaged fallopian tubes
• Endometriomas (ovarian cysts) that reduce ovarian reserve
• Inflammatory environment that may affect egg quality and embryo implantation

The good news: most women with mild to moderate endometriosis can conceive naturally. For those who cannot, the National Institute of Child Health and Human Development outlines several effective fertility options, including ovulation induction, intrauterine insemination (IUI), and in vitro fertilization (IVF). Pregnancy itself often temporarily improves symptoms, as the hormonal environment of pregnancy suppresses endometriotic tissue.

If you’re navigating fertility challenges and exploring alternative paths to parenthood, the CoParents community connects people considering co-parenting, sperm donation, and other family-building options.

What is the emotional impact of endometriosis?

Living with chronic pain, fatigue, and fertility uncertainty takes a measurable mental toll. Studies show that women with endometriosis experience anxiety and depression at rates substantially higher than the general population. The long delay before diagnosis — often years of being told the pain is “normal” — adds a psychological burden many describe as medical gaslighting.

Multidisciplinary care that includes psychological support, peer communities, and pain management has been shown to significantly improve quality of life. Asking for help is not optional; it is part of effective treatment.

Frequently asked questions about endometriosis

Can endometriosis go away on its own?

No. Endometriosis is a chronic condition, and lesions rarely disappear without treatment. However, symptoms typically improve after menopause as estrogen levels drop. Pregnancy and breastfeeding can also temporarily ease symptoms by suppressing the menstrual cycle.

Can I get pregnant if I have endometriosis?

Yes, most women with endometriosis can conceive, especially with mild to moderate disease. About two thirds of women with the condition do not experience fertility issues at all. For those who do, treatments range from surgery to remove lesions to assisted reproductive techniques such as IUI and IVF, with success rates that depend on disease severity and age.

Is endometriosis the same as fibroids or PCOS?

No. Endometriosis involves uterine-like tissue growing outside the uterus. Fibroids are noncancerous muscle tumors growing within the uterine wall. PCOS is a hormonal disorder affecting ovulation. The three conditions can coexist but require different diagnostic approaches and treatments.

Does diet affect endometriosis?

Evidence is still emerging, but anti-inflammatory eating patterns rich in fruits, vegetables, omega-3 fatty acids, and whole grains may help reduce symptoms for some women. Diets high in red meat, processed foods, and trans fats have been associated with higher endometriosis risk in observational studies.

How long does it take to get diagnosed with endometriosis?

The global average diagnostic delay is 4 to 12 years. Early advocacy for your symptoms — keeping a pain and cycle diary, requesting referral to a specialist gynecologist, and asking specifically about endometriosis — can significantly shorten this wait.

If endometriosis is making your path to parenthood harder, you don’t have to face it alone. Join the CoParents community to find a co-parent or sperm donor, share experiences with others who understand fertility challenges, and explore family-building options that fit your story.