Endometriosis: symptoms, diagnosis and diagnostic delay
In brief
The main symptoms of endometriosis are very painful periods (dysmenorrhoea), deep pain during sex, bowel or urinary pain during periods, and difficulty getting pregnant. Endometriosis is a chronic disease in which tissue similar to the lining of the uterus grows outside the uterus; it is called deep endometriosis when the lesions extend more than 5 mm below the peritoneum. According to the French CNGOF-HAS guidelines (French College of Gynaecologists and Obstetricians and French National Authority for Health), the first-line examinations are the gynaecological examination and pelvic ultrasound, then, in case of doubt, a transvaginal ultrasound by a specialist sonographer and/or a pelvic MRI. The time between the first symptoms and diagnosis is still estimated at several years, largely because painful periods are often wrongly considered "normal".
What is endometriosis?
The endometrium is the lining of the inside of the uterus, which is renewed with each cycle. In endometriosis, endometrial-type cells implant outside the uterus: on the peritoneum (the membrane covering the pelvic organs), on the ovaries, or deeper in the ligaments, the wall between the vagina and rectum, the rectum, the colon or the bladder.
According to the CNGOF-HAS guidelines (2017–2018), its exact frequency is unknown; it is often estimated at around one woman in ten of reproductive age. These lesions remain sensitive to the hormones of the cycle. They cause local inflammation, sometimes adhesions (organs sticking to each other) and ovarian cysts called endometriomas.
Three forms are classically distinguished, which may coexist:
- superficial (or peritoneal) endometriosis: small lesions on the surface of the peritoneum;
- endometrioma: an ovarian cyst containing thick brown fluid ("chocolate cyst");
- deep endometriosis: lesions that extend more than 5 mm below the peritoneum and can affect the digestive tract, the ureters or the bladder.
According to the French guidelines, endometriosis that causes no symptoms requires no treatment, monitoring or screening. Care is justified when there is pain, infertility or impaired function of an organ.
Which symptoms should suggest endometriosis?
The 2018 CNGOF-HAS guidelines describe several suggestive symptoms, particularly when they increase at the time of the period:
- very painful periods (severe dysmenorrhoea), which require strong painkillers, cause missed school or work, or do not respond to anti-inflammatory drugs;
- deep pain during sexual intercourse (deep dyspareunia), felt deep in the vagina and not at the entrance;
- pain on opening the bowels during periods, sometimes cyclical bowel disturbances (diarrhoea, constipation, bloating);
- urinary symptoms during periods: burning, frequent urge to pass urine, more rarely blood in the urine;
- chronic pelvic pain, present outside periods;
- difficulty getting pregnant.
More rarely, shoulder or chest pain at the time of the period may reveal endometriosis of the diaphragm.
Does the intensity of symptoms reflect the extent of the disease?
No. A few superficial lesions can be very painful, whereas extensive deep endometriosis may cause few symptoms. This is why the assessment covers both the lesions and their impact: intensity of pain, quality of life, sex life, work. Validated questionnaires can help measure this impact objectively.
Why does diagnosis take so long?
The diagnostic delay for endometriosis is frequently estimated at several years in published studies. Several reasons explain this:
- painful periods being treated as normal, by those around the patient and sometimes by healthcare professionals;
- digestive or urinary symptoms that first point towards other specialties;
- a contraceptive pill taken for other reasons, which can ease the pain and mask the disease;
- a standard ultrasound that may be normal, particularly in superficial forms.
A normal ultrasound therefore does not rule out endometriosis. When the symptoms are suggestive, it is legitimate to ask for a specialist opinion.
How is the diagnosis made?
The CNGOF-HAS guidelines organise the diagnosis into two levels.
| Level | Examination | What it provides |
|---|---|---|
| First line | Medical history and gynaecological examination | Search for nodules or tender points, particularly behind the cervix |
| First line | Pelvic ultrasound (transvaginal if possible) | Identifies endometriomas, sometimes deep nodules |
| Second line | Clinical examination by a specialist gynaecologist | Targeted examination of the deep areas of the pelvis |
| Second line | Transvaginal ultrasound by a specialist sonographer | Mapping of deep lesions, search for bowel involvement |
| Second line | Pelvic MRI | Overall view of the pelvis, deep lesions, ovaries, associated adenomyosis |
| Specialised assessment | Rectal endoscopic ultrasound, CT colonography, urinary tests | Only in the case of bowel or urinary involvement, before surgery |
Second-line ultrasound and MRI provide different and complementary information. Their performance depends heavily on the operator's experience: this is why the guidelines refer to examinations "by an expert".
Is a laparoscopy needed to confirm the diagnosis?
For a long time, laparoscopy (a surgical examination under general anaesthesia) with analysis of the lesions was considered the reference examination. This is no longer the case. The French guidelines state that diagnostic laparoscopy should only be considered when clinical suspicion is strong despite normal imaging, and only if it is part of a plan to treat pain or infertility.
In practice, hormonal treatment can be started on the basis of clinical and imaging findings, without prior surgical proof.
What is the #Enzian classification?
Several classifications exist to describe endometriosis. The oldest, the rASRM classification, assigns a stage from I to IV but describes deep endometriosis poorly.
The #Enzian classification, published in 2021 by a group of European experts, was designed to map the disease as a whole:
- peritoneal lesions (P);
- the ovaries (O);
- adhesions around the tubes and ovaries (T);
- the deep compartments: rectovaginal septum and vagina (A), ligaments and pelvic wall (B), rectum (C);
- other deep locations (F): bladder, ureters, higher bowel, etc.
Its particular feature is that it can be used from ultrasound or MRI as well as during surgery. It facilitates communication between radiologist, gynaecologist and surgeon, and allows the state of the lesions to be compared over time. For the patient, it results in a more precise report, without in itself changing the treatment decision.
What happens once the diagnosis is made?
Management depends on three questions: the intensity of the pain, whether there is a plan for pregnancy, and the location of the lesions.
- Pain without a plan for pregnancy: hormonal treatment is the first step (see Endometriosis: hormonal treatments and pain relief).
- Wish for pregnancy or infertility: the strategy is discussed between surgery and medically assisted reproduction (see Endometriosis and fertility: surgery or IVF first?).
- Failure of medical treatment, bowel or urinary involvement: surgery may be offered, after discussion at a multidisciplinary team meeting (see Endometriosis surgery: indications, technique and recovery).
The guidelines insist on providing the patient with complete information: treatment alternatives, expected benefits and risks, risk of recurrence and consequences for fertility.
Endometriosis and adenomyosis: what is the difference?
Adenomyosis is a related disease in which endometrial tissue penetrates the muscle of the uterus (the myometrium). It mainly causes heavy and painful periods. The two diseases are often associated, and MRI can look for both during the same examination. See our article on adenomyosis.
When to seek urgent care?
Endometriosis is generally not an emergency, but certain signs require a prompt consultation, or even a call to 15 (SAMU) or 112 in France, or your local emergency number:
- sudden and intense lower abdominal pain, especially if you have a known ovarian cyst (risk of torsion or rupture);
- fever associated with pelvic pain;
- inability to pass wind or stools with vomiting (bowel obstruction, exceptional);
- persistent pain in the lower back on one side, which may indicate compression of a ureter.
Frequently asked questions
Is endometriosis hereditary?
There is a family component: the risk is higher when a mother or sister is affected. This does not mean that the disease is systematically passed on, and no screening is recommended for a woman without symptoms.
Can a teenager have endometriosis?
Yes. Very painful periods from adolescence, with missed school, justify a consultation. For adolescents, the French guidelines favour an adapted clinical examination, ultrasound or MRI, and first-line hormonal treatment.
Can a blood test diagnose endometriosis?
No blood marker is currently recommended for making the diagnosis. The CA 125 test, sometimes prescribed, is neither sensitive nor specific enough.
Does endometriosis always get worse?
No. Its course is unpredictable: lesions may remain stable, regress or progress. Symptoms generally decrease after the menopause, when the production of ovarian hormones stops.
Does endometriosis increase the risk of cancer?
A slight increase in the risk of certain ovarian cancers has been described, but the absolute risk remains low. No specific screening is recommended beyond the usual gynaecological follow-up.
References
- Fauconnier A, et al. — [Epidemiology and diagnosis strategy: CNGOF-HAS Endometriosis Guidelines]. Gynecol Obstet Fertil Senol, 2018 — doi:10.1016/j.gofs.2018.02.012 — PMID 29548620
- Collinet P, et al. — Management of endometriosis: CNGOF/HAS clinical practice guidelines - Short version. J Gynecol Obstet Hum Reprod, 2018 — doi:10.1016/j.jogoh.2018.06.003 — PMID 29920379
- Keckstein J, et al. — The #Enzian classification: A comprehensive non-invasive and surgical description system for endometriosis. Acta Obstet Gynecol Scand, 2021 — doi:10.1111/aogs.14099 — PMID 33483970
Dr Olivier KadochObstetrician-gynaecologist and gynaecological surgeon in Paris (16th and 5th arrondissements). Former chef de clinique-assistant (senior registrar) at the Paris public hospitals (AP-HP); individually accredited by the French National Authority for Health (HAS). RPPS 10003957809. Background and practice locations
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