The average age of onset of pain symptoms in women with endometriosis is 21 years old but the average age of diagnosis is 28. This may be because many women ignore the pain symptoms because they think it must be normal and do not wish to appear as if they are complaining, or because doctors dismiss their complaints too easily.
Your gynaecologist may be able to get an idea that you may have endometriosis from asking about your symptoms. Normally they will arrange for you to have a standard transvaginal ultrasound scan which can usually diagnose endometriotic cysts in ovaries (endometriomas). A scan by an expert endometriosis scanner can detect deep infiltrating endometriosis and other rarer presentations of endometriosis and adenomyosis, however this is not a skill available to most operators performing general gynaecological scans meaning that deep infiltrating endometriosis would usually be missed on a standard scan. Superficial endometriosis is not reliably confirmed or refuted on any form of scan currently. If you are not sexually active the scan can be done transrectally instead.
MRI may also be used to diagnose deep infiltrating endometriosis if it is suspected. Transvaginal ultrasound in expert hands may be better in some ways as it is cheaper and more accessible and in expert hands gives a dynamic picture since organs can be pushed against each other to find out where adhesions are.
Some general gynaecologists test an antigen in the blood called CA125. This test is used as a marker for ovarian cancer patients and is also often raised in deep infiltrating endometriosis to the same extent. Most experts do not recommend its use because it is an emotive test that unnecessarily and wrongly scares people about a risk of cancer that is not there. In expert hands the risk of cancer is more readily assessed on the transvaginal ultrasound or MRI.
As described above, minimal to mild endometriosis (stage 1-2) cannot be detected by any test or scan and the only way to diagnose it is to undergo a diagnostic laparoscopy (keyhole surgery) under general anaesthetic and to see it directly and ensure that the surgeon will remove it by excision at the same time. If your doctor suspects or finds you to have more severe disease affecting the bowels, bladder or ureters that was missed due to having a standard, rather than expert transvaginal scan or MRI, you would likely need to be woken up to undergo further specialist tests and counselling to assess the problem before proceeding to complex surgery if appropriate. An expert centre will know from your first assessment if you have severe disease and avoid the need for a diagnostic laparoscopy to find it.
It is crucial that your endometriosis treatment is tailored to your own specific circumstances and that you see a specialist in endometriosis who can advise you on this. Your treatment will depend upon your age, desire for a diagnosis, fertility requirements and pain symptoms. Do not just accept the first treatment offered without understanding why it is being offered in your situation. A consultation for complex endometriosis will take a good 60 minutes.
Our approach to diagnosis