The clinical features and diagnosis of endometriosis

The following symptoms have been associated with endometriosis:

  • Severe dysmenorrhoea (painful periods)
  • Deep dyspareunia (pain on intercourse)
  • Chronic non-menstrual pain
  • Pain at the time of ovulation
  • Dyschezia (pain on defaecation, especially at the time of menstruation)
  • Cyclical or perimenstrual symptoms, affecting the bowel or bladder, with or without abnormal bleeding or pain
  • Subfertility (difficulty conceiving for more 12 months)
  • Chronic fatigue

However, the predictive value of any one symptom or set of symptoms is uncertain because of the overlap with other conditions, such as irritable bowel syndrome, interstitial cystitis, pelvic inflammatory disease, fibromyalgia and musculoskeletal disorders (ASRM Practice Committee – Pain, 2006.). The difficulties inherent in interpreting such symptoms contribute to the well-recognised delay of up to 10 years between the onset of symptoms and a surgical diagnosis.
Endometriosis should be suspected in women of reproductive age who present with such symptoms, especially if there is a cyclical component. A history and pelvic examination should be performed. There is evidence to suggest that performing the examination during menstruation helps to make the diagnosis, although many women are reluctant to be examined at that time.

The pelvic examination may be entirely normal, but features suggestive of endometriosis include:

  • Generalised pelvic tenderness
  • Fixed, retroverted uterus (due to adhesions and/or deeply infiltrating disease)
  • Tender uterosacral ligaments (nodules may also be palpable)
  • Enlarged ovaries
  • Seeing lesions/nodules in the vagina or on the cervix

The diagnosis may be suspected on clinical grounds but it can only be confirmed on visual inspection of the peritoneal cavity at laparoscopy. Histological confirmation of at least one lesion represents ideal practice, although if an endometrioma > 4 cms in diameter or deeply infiltrating disease is present, histology should be obtained to exclude rare instances of malignancy.

Disease severity should be assessed by documenting in detail the type, location and extent of all lesions and adhesions found at surgery. Ideal practice is to record the findings on video or DVD as well. Disease severity can be assessed quantitatively using a classification system such as the one developed by the American Society for Reproductive Medicine (ASRM). However, there is no correlation between such systems and the type or severity of pain symptoms.

Diagnostic laparoscopy is associated with an approximately 3% risk of minor complications, such as nausea or shoulder-tip pain, and a risk of major complications, such as bowel perforation, of between 0.6 to 1.8 per 1,000 procedures. Therefore, a non-invasive test would be clinically useful.

The following tests have been used with varying degrees of success:

  • Serum CA-125 (a test for ovarian cancer) – levels may be elevated in endometriosis but the test has little diagnostic value and is not recommended
  • Trans-vaginal ultrasound – a useful tool to make and exclude the diagnosis of an ovarian endometrioma, but it has limited value in diagnosing peritoneal disease.
  • Magnetic resonance imaging (MRI) – there is insufficient evidence at present regarding its diagnostic potential; however, MRI and other imaging modalities (e.g. transrectal ultrasound, IVP, barium enema) may have a role in defining disease extent in deeply infiltrating endometriosis.

If a woman with symptoms suggestive of endometriosis wants treatment without a definitive diagnosis, the options include counselling, analgesia and hormonal medication to reduce menstrual flow (e.g. progestagens or COC). It is unclear whether the COC should be taken conventionally, continuously or in a tricycle regimen in such circumstances.

A gonadotrophin-releasing hormone (GnRH) agonist may be taken, although this is an expensive option and concerns exist about the effects on bone mineral density (BMD). It is also argued that establishing the correct diagnosis at laparoscopy before initiating therapy with significant short- and long-term side effects is the preferred approach (ASRM Practice Committee – Pain, 2006).


The Practice Committee of the American Society for Reproductive Medicine (2006).Treatment of pelvic pain associated with endometriosis. Fertility & Sterility 2006 Nov; 86 (5 SUPPL.).