Complete medical guide

What is endometriosis?

If you have reached this page, you likely already know what it means to have years of pain invalidated by doctors. Endometriosis is a chronic condition in which tissue similar to the endometrium (the uterine lining) grows outside the uterus — on the ovaries, fallopian tubes, peritoneum, and sometimes on the bladder or bowel. It affects approximately 10% of women of reproductive age — about 190 million people globally, according to the WHO.

Andrei Simon · Science of Life PHARMA | Updated: March 2026 | Based on 318+ peer-reviewed references | 2022 ESHRE Guidelines · 2025 WHO

Table of Contents

  1. What is endometriosis — definition
  2. Symptoms of endometriosis
  3. Causes and risk factors
  4. Biological mechanisms
  5. Diagnosis
  6. Treatment options
  7. Diet and lifestyle
  8. Frequently asked questions
10% din femeile de vârstă reproductivă afectate 7–10 ani de întârziere diagnostică 40% din cazurile de infertilitate feminină 40–50% rată de recurență post-chirurgicală (5 ani) Surse: Zondervan et al., Nat Rev Dis Primers 2018 · ESHRE Guidelines 2022

Key statistics — endometriosis by the numbers

Key facts — endometriosis

  • Endometriosis is a chronic, estrogen-dependent inflammatory condition in which functional endometrial tissue (glands and stroma) grows outside the uterus — on the ovaries, peritoneum, fallopian tubes, or bowel.
  • It affects about 10% of women of reproductive age — approximately 190 million people globally (World Health Organization, 2025).
  • Average diagnostic delay: 7–10 years — due to symptom overlap with irritable bowel syndrome, cystitis, and primary dysmenorrhea.
  • Endometriosis is present in 30–50% of women with infertility. Mechanisms include tubal obstruction, alteration of the peritoneal microenvironment, and reduced ovarian reserve (ESHRE 2022).
  • Post-surgical recurrence rate: 40–50% at 5 years without maintenance treatment (ESHRE Endometriosis Guideline 2022).
  • Documented biological mechanisms: chronic inflammation, oxidative stress, VEGF angiogenesis (vascular proliferation), and dysfunctional estrogen metabolism — each representing a distinct therapeutic axis.

Definition

What is endometriosis — clinical definition

Endometriosis is a chronic, estrogen-dependent inflammatory condition characterized by the presence of functional endometrial tissue (glands and stroma) outside the uterine cavity. These lesions respond to hormonal fluctuations during the menstrual cycle—growing and bleeding cyclically, generating local inflammation, scarring, and adhesions.

Simplified definition

The lining that covers the uterus grows outside of it — on the ovaries, peritoneum, fallopian tubes, or bowel. It bleeds monthly, like the normal lining, but the blood has nowhere to exit. The result: chronic inflammation, pain, and, over time, scarring.

There are three main forms:

  • Superficial peritoneal endometriosis — small lesions on the surface of the peritoneum (the membrane lining the abdominal organs).
  • Ovarian endometriomas (endometriotic cysts) — collections of old blood on the ovaries, popularly known as "chocolate cysts."
  • Deep infiltrative endometriosis (DIE) — the most severe form, in which the lesions penetrate more than 5mm into the surrounding tissues: uterosacral ligaments, rectum, bladder, ureter.

Endometriosis should not be confused with adenomyosis — a distinct condition in which endometrial tissue grows into the muscular wall of the uterus (myometrium). The two can coexist and have partially similar biological mechanisms.

Symptoms of endometriosis

Endometriosis symptoms

Symptoms vary considerably among patients—some experience debilitating pain, while others are asymptomatic and only discover the condition during infertility investigations. The absence of pain does not exclude endometriosis.

Main symptoms

  • Severe dysmenorrhea — intense menstrual pain that does not respond to common anti-inflammatory drugs (ibuprofen, naproxen) or only responds partially.
  • Chronic pelvic pain — present even between periods, sometimes permanent. It may radiate to the back, thighs, or rectum.
  • Dyspareunia — pain during sexual intercourse, especially with deep penetration. Common when endometriosis affects the uterosacral ligaments or the pouch of Douglas.
  • Heavy menstrual bleeding (menorrhagia) or intermenstrual bleeding (spotting).
  • Chronic fatigue — often underestimated as a symptom; it is frequent and debilitating, amplified by systemic inflammation.

Other common symptoms

  • Digestive symptoms — bloating, constipation, or diarrhea (especially perimenstrually), painful bowel movements. Frequent when endometriosis affects the rectum or sigmoid colon.
  • Urinary symptoms — frequent or painful urination, especially perimenstrually, when endometriosis involves the bladder.
  • Difficulty getting pregnant — endometriosis is present in 30–50% of women with infertility.

Why does it take so long to get a diagnosis?

The average of 7–10 years to reach a diagnosis has several causes: symptoms are socially normalized ("menstrual pain is normal"), there is overlap with other conditions (irritable bowel syndrome, cystitis), and a definitive diagnosis requires laparoscopy — there is no definitive blood test. Early diagnosis significantly reduces disease progression.

Causes and risk factors

Causes of Endometriosis — What Science Knows

The exact cause of endometriosis remains incompletely elucidated. Current research supports a multifactorial model—no single theory explains all cases.

Main theories

  • Retrograde menstruation (Sampson theory, 1927) — menstrual blood containing endometrial cells refluxes through the fallopian tubes into the abdominal cavity and implants. It occurs in 90% of women, but endometriosis develops only in some — which suggests that immunological dysfunction plays a determining role.
  • Coelomic metaplasia — peritoneal cells transform into endometrial cells under the influence of hormonal or inflammatory stimuli. This explains thoracic endometriosis and rare cases in men.
  • Immunological dysfunction — the immune system does not efficiently eliminate ectopic endometrial cells. Increased levels of pro-inflammatory cytokines (IL-6, IL-8, TNF-α) in the peritoneal fluid favor the survival and proliferation of lesions.
  • Genetic factors — the risk is 7–10× higher if a first-degree relative has endometriosis. Genome-wide association studies (GWAS) have identified multiple susceptibility loci.
  • Endocrine disruptors — exposure to dioxins, polychlorinated biphenyls (PCBs), and other substances with estrogenic activity in the environment can increase the risk and accelerate progression.

Biological mechanisms

Biological mechanisms of endometriosis

Understanding biological mechanisms is essential for choosing an effective therapeutic approach. Endometriosis is not a single biological problem — there are four simultaneous mechanisms that fuel one another.

Axis 1

Chronic inflammation

NF-κB · IL-6 · COX-2 · PGE2

The lesions produce pro-inflammatory cytokines that sustain pelvic pain and stimulate disease progression. The inflammatory cycle is self-perpetuating — each menstruation amplifies the response.

Axis 2

Pathological angiogenesis

VEGF · HIF-1α · MMP-2 · MMP-9

Lesions build their own vascular network by overexpressing VEGF, ensuring a supply of oxygen and nutrients for survival and expansion.

Axis 3

Oxidative stress

ROS · Glutathione ↓ · Nrf2 · Cu/Zn-SOD

Increased levels of reactive oxygen species (ROS) and glutathione deficiency in peritoneal fluid exacerbate inflammation and promote ectopic implantation.

Axis 4

Estrogen metabolism

Aromatase · CYP19A1 · ERβ · 2-OHE1

Lesions produce estrogen locally by upregulating aromatase (CYP19A1), creating a hyperestrogenic microenvironment that stimulates their own proliferation.
AXA 1 Inflamație cronică COX-2 · IL-6 · TNF-α PGE2 · NFκB AXA 2 Angiogeneză patologică VEGF · HIF-1α · FGF AXA 3 Stres oxidativ ROS · Glutation ↓ Nrf2 · Cu/Zn-SOD AXA 4 Metabolism estrogenic Aromatază · CYP19A1 Ciclu biologic cronicizat (self-sustaining)

The 4 biological axes of endometriosis amplify each other, forming a chronicized cycle

"Most treatments address a single axis. Endometriosis involves all four — at the same time."

This complexity explains why a single medication or supplement rarely controls the disease completely: surgical treatment removes visible lesions but does not alter the inflammatory microenvironment; hormonal treatment suppresses systemic estrogen but does not address angiogenesis or oxidative stress.

Diagnostic

Endometriosis diagnosis

The definitive diagnosis of endometriosis is achieved through laparoscopy with histopathological biopsy — the gold standard, but an invasive surgical procedure. Non-invasive methods may suggest the diagnosis, but they do not confirm it.

Investigation methods

  • Transvaginal ultrasound — first-line method. Detects endometriotic ovarian cysts and, in specialized centers, deep lesions. Operator-dependent — accuracy varies.
  • Pelvic MRI — superior to ultrasound for deep endometriosis and adenomyosis. Useful for preoperative planning in complex cases.
  • CA-125 — tumor marker with limited value: elevated in severe endometriosis, but also in other conditions. Not a screening test.
  • Diagnostic laparoscopy — the only method that confirms the diagnosis with certainty. Also allows for the simultaneous treatment of visible lesions.

Important

A normal ultrasound scan does not exclude endometriosis. Superficial peritoneal lesions and small deep lesions are not visible on ultrasound. If symptoms are suggestive, a consultation with a gynecologist specializing in endometriosis is recommended.

Treatment options

Endometriosis treatment options

There is no curative treatment for endometriosis—the therapeutic goal is symptom management, reducing progression, and improving quality of life. The choice of treatment depends on the severity, age, desire for fertility, and the patient's preferences.

Category: Analgesic treatment

Options: NSAIDs (ibuprofen, naproxen), analgesics, COX-2 inhibitors

Notes: Short-term pain management. Does not modify disease progression. First-line for mild-to-moderate pain.

Category: Hormonal treatment

Options: Dienogest (Visanne®, Zafrilla®), progestogens, combined oral contraceptives, levonorgestrel IUD, GnRH analogues

Notes: Suppresses estrogenic activity, reduces lesions. Effective for symptoms in 70–80% of cases. Contraindicated if planning pregnancy immediately.

Category: Surgical treatment

Options: Conservative laparoscopy (excision/ablation of lesions), ovarian cystectomy, deep resection

Notes: Removes visible lesions, alleviates pain, and may improve fertility. Recurrence rate of 40–50% at 5 years without maintenance treatment.

Category: Non-hormonal biological support

Options: Multi-axial nutraceuticals (NAC, polyphenols, DIM, Vitamin D3), natural anti-inflammatories

Notes: Addresses inflammatory, oxidative, and angiogenic mechanisms without systemic hormonal suppression. Can be used as a complement to hormonal or surgical treatment.

Category: Fertility treatment

Options: IVF, IUI, supervised ovarian stimulation

Notes: Indicated when fertility is compromised. Moderate-to-severe endometriosis reduces ovarian reserve.

Detailed guide on treatment options, efficacy comparison, and long-term management: Clinical references and peer-reviewed evidence →

None of the categories in the table above address all 4 mechanisms simultaneously

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Diet and lifestyle

Diet and lifestyle in endometriosis

There is no "endometriosis diet" validated by randomized clinical trials. However, evidence from literature and biological mechanisms support the value of an anti-inflammatory lifestyle—which can reduce symptom intensity and slow progression, as a complement to medical treatment.

Anti-inflammatory dietary principles

  • Omega-3 (EPA/DHA) — fatty fish (salmon, sardines, mackerel), flax seeds, walnuts. Modulates the synthesis of pro-inflammatory prostaglandins (PGE2).
  • Dietary antioxidants — colorful vegetables and fruits (tomatoes, spinach, blueberries, broccoli). Reduce peritoneal oxidative stress.
  • Reduction of pro-inflammatory foods — refined sugar, processed vegetable oils (excess omega-6), processed meat. Limiting alcohol and coffee during painful periods.
  • Fiber and cruciferous vegetables — broccoli, cabbage, cauliflower contain natural DIM and support hepatic estrogen metabolism.
  • Avoiding endocrine disruptors — reducing exposure to plastic (BPA), pesticides, cleaning products with synthetic fragrances.

Physical activity and stress management

Moderate physical activity (yoga, swimming, walking) can reduce circulating estrogen levels and alleviate chronic pelvic pain by releasing endorphins and reducing systemic inflammation. Chronic stress amplifies inflammation via the HPA axis—stress management techniques (meditation, mindfulness) have a demonstrated impact on the perception of chronic pain.

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Detailed guides

Explore every aspect of endometriosis in the specialized guides below.

Guide

Treatment options

Read the guide →

Guide

Anti-inflammatory diet and lifestyle

Read the guide →

Related condition

What is adenomyosis?

Read the guide →

Real evidence

Other women's experiences with endometriosis

Read the testimonials →

Company

About Science of Life Pharma

Read →

Frequently Asked Questions

Frequently asked questions about endometriosis

Can endometriosis be cured?

There is currently no curative treatment for endometriosis. Surgery removes visible lesions, but the recurrence rate is 40–50% at 5 years without maintenance therapy. Natural or surgical menopause usually leads to the regression of the disease, but it is not an acceptable option for young women. The current therapeutic goal is the long-term management of symptoms and disease progression.
Does endometriosis cause infertility?

Endometriosis is present in 30–50% of women with infertility. The mechanisms involved include: mechanical tubal obstruction, alteration of the peritoneal microenvironment, reduced oocyte quality due to chronic inflammation, and decreased ovarian reserve in cases of repeatedly operated ovarian cysts. However, many women with endometriosis become pregnant naturally or with reproductive medical assistance (IVF, IUI).
What is adenomyosis and how does it differ from endometriosis?

In adenomyosis, endometrial tissue grows into the muscular wall of the uterus (myometrium) instead of spreading outside the uterus. Typical symptoms include heavy menstrual bleeding, an enlarged uterus, and diffuse pain (not necessarily focused in the pelvic area). Adenomyosis and endometriosis frequently coexist and share some biological mechanisms (inflammation, estrogen metabolism). Complete guide to adenomyosis →
Can endometriosis be diagnosed without a laparoscopy?

A definitive diagnosis requires laparoscopy with biopsy. However, the current 2022 ESHRE guidelines state that a clinical diagnosis based on typical symptoms and a transvaginal ultrasound performed by a specialist may be sufficient to initiate empirical treatment, without the need for laparoscopy in all cases. A high-quality pelvic MRI complements the assessment in complex cases.
Does endometriosis recur after surgery?

Yes. The recurrence rate is 40–50% at 5 years after conservative surgery (excision/ablation of lesions), without maintenance treatment. Postoperative hormonal treatment (dienogest, contraceptives) significantly reduces recurrence. Non-hormonal biological support addressing inflammatory and angiogenic mechanisms can complement the maintenance strategy, upon the physician's recommendation.
Can I take supplements or nutraceuticals alongside hormone therapy?

Many patients use nutritional support to complement hormonal treatment. ENDORA™, for example, does not contain hormones and does not interfere with the hypothalamic-pituitary-gonadal axis — it can be used as a complement to dienogest (Zafrilla®, Visanne®), oral contraceptives, or GnRH analogs. Consult your gynecologist before adding any product, especially if you are undergoing a fertility protocol.
Which specialists treat endometriosis in Romania?

Endometriosis is diagnosed and treated by gynecologists with additional specialization in laparoscopic surgery for complex cases. Dedicated endometriosis centers (SEUD-accredited) offer multidisciplinary teams that include gastroenterologists and urologists for deep-infiltrating forms. Patient associations in Romania can provide recommendations for specialists experienced in endometriosis.

Scientific references

  1. World Health Organization. Endometriosis [Fact sheet]. Updated October 2025. who.int
  2. ESHRE Endometriosis Guideline Development Group. Endometriosis: ESHRE Guideline. European Society of Human Reproduction and Embryology; 2022. eshre.eu
  3. PMID 23737821
  4. Tsamantioti ES, Mahdy H. Endometriosis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024. ncbi.nlm.nih.gov
  5. PMID 32430755
  6. Moradi Y, Shams-Beyranvand M, Khateri S, et al. A systematic review on the prevalence of endometriosis in women. Indian J Med Res. 2021;154(3):446–454. PMID 35345070
  7. PMID 30001982