Current thinking on endometriosis

Endometriosis is a poorly understood disease, traditionally defined as the presence of hormonally dependent endometrium (the lining of the uterus shed at periods) outside the uterus. It should be emphasized that recent research has revealed that endometriosis is in fact a chronic systemic inflammatory disease and the current definition should probably be expanded.1  The average time to diagnosis has been estimated at more than 10 years although a provisional diagnosis with appropriate ongoing management is reasonable.

Several theories exist as to the cause

Exciting new evidence reveals that the underlying problem may lie within the uterus in the zone between the endometrium (which is shed at menstruation) and the myometrium (the muscle of the uterus). Our research team at Sydney University have demonstrated the striking finding that patients with endometriosis have nerve fibers in the lining of their uterus (ie the “normal” endometrium) whilst those without the disease do not have these nerve fibers.2  We initially thought this may allow for diagnosis without invasive laparoscopy although in practice this has not eventuated. Others have shown the possibility that stem cells in this region are implicated in the development of endometriosis.3  Endometriosis might thus be the first stem cell disease described.

More traditional theories include retrograde menstruation and metaplasia.

Why do people get endometriosis?

This remains unclear. Anecdotally, endometriosis appears to be getting more common and possibly more severe. There must be some reason in nature for this. Exposure to “endocrine disruptors” such as bisphenol A (BPA) have been implicated.New, somewhat controversial evidence, suggests that endometriosis may decrease the chance of pre-eclampsia (fitting and high blood pressure) in pregnancy.5  Thus it might actually be that endometriosis is protective for pregnancies, particularly if you are very young, but becomes a problem if you defer pregnancy or get a bigger “dose” of endometriosis.6


Our new endometrial biopsy test outlined above and possible other non-invasive tests will dramatically alter the management of the disease in years to come. The cornerstone of diagnosis has been a good clinical history. Premenstrual spotting and cyclical symptoms, particularly pain, are good indicators. Examination is usually normal, although at times nodules can be felt on vaginal examination in the region of the uterosacral ligaments. A standard pelvic ultrasound may reveal an endometrioma which usually means more significant and higher stage disease with possible bowel involvement.7  More recently new techniques have evolved with transvaginal ultrasound to enable the diagnosis of deep invasive endometriosis (DIE scan). Alternatively MRI is also capable of diagnosing deep invasive disease. Superficial disease is more difficult to image.


We know that pregnancy appears to decrease the severity of the disease and may even clear it. The contraceptive pill is also useful, although up to 30% of women will not have a response.1 Medical therapy has a role in maintenance but unfortunately does not result in longstanding regression or cure. All agents are contraceptive and there is no data to suggest an improvement in fertility rates. Unfortunately, many have significant side effects.  In most cases the areas containing endometriosis are reasonably superficial but they can at times be deeply invasive and cause significant scarring and fibrosis not unlike a malignant process. Surgery is thus often necessary.

The surgical philosophy in recent times has moved towards an excisional approach rather than simple diathermy techniques.8,9  To a certain extent endometriosis may be likened to an iceberg and diathermy may result in residual disease. Diathermy is also unsuitable for many situations with disease adjacent to bowel or ureters. Excisional surgery results in a 70 to 80% chance of substantial ongoing pain relief with an increase also in fertility rates.10-12  The best results paradoxically occur in those with the most severe disease (such as illustrated). Most of these procedures can be done via laparoscopy. Our data and audits are in accord with these results and show low complication rates.13

Combined treatment approaches

Given the inflammatory nature of the disease, the findings we have demonstrated in the uterus of people with endometriosis and the other associated abnormalities, I have been recommending most patients either try and get pregnant following surgery or contemplate placing a Mirena device which secretes a progestogen and “mimics” pregnancy. This appears the best method of decreasing the risk of recurrence whilst maintaining fertility.

Pain Control

This can be exceedingly difficult and most patients will find that traditional pain medications will become minimally effective with the passage of time. There are new long acting agents which are useful for acute exacerbation. The situation can enter a vicious circle. New insights into the origin of pain can assist. I suggest patients watch this excellent video. There are also two books explaining things in a different but similar way: Why Does it Still Hurt? and Why Pelvic Pain Hurts.

Specialist physiotherapists can assist with relaxing the pelvic floor and can be extremely helpful.


Endometriosis is a chronic systemic inflammatory disease. Therefore, I recommend lifestyle measures to decrease inflammation. These include diet, timed fasting, exercise, hot/cold showers or baths, acupuncture, mindfulness, meditation decreasing stress and the like. Additionally there appear to be benefits with the use of anti-inflammatory supplements such as Tumeric (500mg day) and N-Acetylcysteine NAC (600mg 3 times a day, 3 consecutive days a week for 3 months)

IVF or surgery for endometriosis?

This is a controversial area and management needs to be individualised. In general terms, IVF success rates are lower if you have endometriosis and there is the possibility of making symptoms worse, so removing the disease before starting IVF is appropriate.

Cancer and endometriosis

In many respects endometriosis is similar to malignancy. There appears to be an increased risk of progression to frank cancer, particularly for those patients who have large ovarian endometriomas.


  1. Taylor HS, Kotlyar AM, Flores VA. Endometriosis is a chronic systemic disease: clinical challenge and novel innovations. Lancet. Feb 2021;397(10276):839-852.
  2. Al-Jefout M, Dezarnaulds G, Cooper M, et al. Diagnosis of endometriosis by detection of nerve fibres in an endometrial biopsy: a double blind study. Hum Reprod. 2009 Dec (Epub 2009 Aug 2009;24(12):3019-24.
  3. Sasson IE, Taylor HS. Stem cells and the pathogenesis of endometriosis. Ann N Y Acad Sci. 2008 2008;1127:106-15.
  4. Simonelli A, Guadagni R, De Franciscis P, et al. Environmental and occupational exposure to bisphenol A and endometriosis: urinary and peritoneal fluid concentration levels. Article. International Archives of Occupational and Environmental Health. Jan 2017;90(1):49-61. doi:10.1007/s00420-016-1171-1
  5. Brosens IA, De Sutter P, Hamerlynck T, et al. Endometriosis is associated with a decreased risk of pre-eclampsia. ; Research Support, Non-U.S. Gov’t. Hum Reprod. 2007 Jun (Epub 2007 Apr 2007;22(6):1725-9.
  6. Brosens I, Derwig I, Brosens J, Fusi L, Benagiano G, Pijnenborg R. The enigmatic uterine junctional zone: the missing link between reproductive disorders and major obstetrical disorders? Hum Reprod. 2010 Mar (Epub 2010 Jan 2010;25(3):569-74.
  7. Redwine DB. Ovarian endometriosis: a marker for more extensive pelvic and intestinal disease. Fertility & Sterility. Aug 1999;72(2):310-315. NOT IN FILE.
  8. Garry R. Laparoscopic excision of endometriosis: the treatment of choice? British Journal of Obstetrics & Gynaecology. May 1997;104(5):513-515. IN FILE.
  9. Redwine DB. Conservative laparoscopic excision of endometriosis by sharp dissection: life table analysis of reoperation and persistent or recurrent disease. Fertility & Sterility. Oct 1991;56(4):628-634. IN FILE.
  10. Berube S, Marcoux S, Maheux R. Characteristics related to the prevalence of minimal or mild endometriosis in infertile women. Canadian Collaborative Group on Endometriosis. Epidemiology. Sep 1998;9(5):504-510. IN FILE.
  11. Berube S, Marcoux S, Langevin M, Maheux R. Fecundity of infertile women with minimal or mild endometriosis and women with unexplained infertility. The Canadian Collaborative Group on Endometriosis. Fertility & Sterility. Jun 1998;69(6):1034-1041. IN FILE.
  12. Marcoux S, Maheux R, Berube S. Laparoscopic surgery in infertile women with minimal or mild endometriosis. Canadian Collaborative Group on Endometriosis [see comments]. New England Journal of Medicine. Jul 24 1997;337(4):217-222. IN FILE.
  13. Kaloo PD, Cooper MJ, Reid G. A prospective multi-centre study of major complications experienced during excisional laparoscopic surgery for endometriosis. EurJ Obstet Gynecol ReprodBiol. 2006;124(1):98-100. NOT IN FILE.