What is endometriosis?

Endometriosis is a disease where tissue similar to the lining of the uterus grows in other parts of the body (Endometriosis Australia 2023). Endometriosis most often affects the reproductive organs but can also be found in other areas, such as around the bowel and bladder. These tissues are collectively known as endometriosis. Endometriosis can cause inflammation and scarring, which can lead to painful ‘adhesions’ joining together pelvic organs which are normally separate.

Endometriosis is a progressive chronic condition. Recent research views endometriosis as an inflammatory, multi-system illness (Saunders et al. 2021; Taylor et al. 2021; Zondervan et al. 2020). There is some evidence to suggest associations exist between endometriosis and other chronic conditions, such as selected cancers and cardiovascular disease (Shafrir et al. 2018).

What causes endometriosis?

The cause of endometriosis is unclear. A family history of endometriosis appears to increase the risk of developing the condition (Jean Hailes for Women’s Health 2023a). Other theories that have been suggested throughout the years are metaplasia (the conversion of normal pelvic tissue into endometriosis) and retrograde (backwards) menstruation (Healthdirect 2021). Other contributing factors may include early age at first period, short menstrual cycles, heavy or long periods, older age of first pregnancy, immune system problems, low body weight, and alcohol consumption.

What are the symptoms of endometriosis?

Symptoms of endometriosis vary between individuals. Some people experience no symptoms, while others experience severe pain, heavy menstrual bleeding, bleeding between periods, abdominal bloating, fatigue, anxiety and depression, among other symptoms (Jean Hailes for Women’s Health 2023a). Pain is a common symptom and can include abdominal, lower back or pelvic pain, painful menstruation, pain during or after intercourse, pain during ovulation, and pain during urination or defaecation. In some cases endometriosis can affect fertility due to the impact on reproductive organs (Jean Hailes for Women’s Health 2023b).

The severity of symptoms does not necessarily reflect the extent of the condition. For example, a person with minimal endometriosis may experience more pain than a person with severe endometriosis (Jean Hailes for Women’s Health 2023a).

Symptoms of endometriosis can occur from menarche (start of menstruation) through menopause (WHO 2021). After menopause, symptoms may ease for many but not for all (Jean Hailes for Women’s Health 2023a).

Diagnosing endometriosis

There are several systems for classifying endometriosis based on the extent and location of the endometriosis, though none have been universally accepted (RANZCOG 2021). It is recommended that treatment is based on symptoms and an individual’s needs, preferences, and priorities for care.

The ‘gold standard’ for definitive diagnosis of endometriosis is a laparoscopic procedure including biopsy and destruction of endometriotic lesions (RANZCOG 2021). However, other methods may be used to reasonably suspect endometriosis and begin treatment without surgery, known as a ‘clinical diagnosis’ (Agarwal et al. 2019; Taylor et al. 2018).

Diagnosis of endometriosis is often delayed, with an average of between 6 and 8 years between onset of symptoms and diagnosis (Armour et al. 2020, O’Hara et al. 2022). Nonspecific symptoms, lack of specific biomarkers, lack of awareness of the condition, and stigma and symptom normalisation have been identified as key contributors to the diagnostic delay (Zondervan et al. 2020). In the study which found an average delay of 8 years, this time was comprised of 3 years from symptom onset to seeking medical care, and 5 years from the first medical appointment to a surgical diagnosis of endometriosis (Armour et al. 2020). However, the diagnostic delay appears to be decreasing over time, both for the time to seeking medical care and time to receiving a diagnosis.

The National Action Plan for Endometriosis

The National Action Plan for Endometriosis was launched in 2018 with the goal of ‘a tangible improvement in the quality of life for individuals living with endometriosis, including a reduction in the impact and burden of disease at individual and population levels’. The plan has 3 priority areas:

  • awareness and education – this involves developing and delivering community awareness campaigns, promoting early education on women’s health in schools, improving access to information for people living with endometriosis, and improving awareness and understanding of endometriosis among health professionals
  • clinical management and care – this involves developing clinical guidelines and clinical care standards; promoting early access to intervention, care and treatment options; improving affordability, accessibility and consistency of management; ensuring endometriosis is recognised as a chronic condition by all health practitioners; and narrowing the gap in quality of life between people with endometriosis and their peers
  • research – this involves building a collaborative environment for endometriosis research, mining existing data and improving data linkage between sources, and conducting further research to understand causes and impacts and progress towards a cure (Department of Health 2018a).

Reducing the prevalence and impact of endometriosis and associated chronic pelvic pain is also listed as a key priority for chronic conditions and preventive health in the National Women’s Health Strategy 2020–2030 (Department of Health 2018b).

Endometriosis data by sex and gender

Endometriosis can affect women and girls, transgender, non-binary, and gender-diverse people assigned female at birth (Department of Health 2018). In this report, terminology used to refer to those experiencing endometriosis is based on that used in the underlying data collection.

Australian Longitudinal Study on Women’s Health (ALSWH 2020a; ALSWH 2020b)
  • 1973–78 cohort: invitations were sent in 1996 based on information from the Medicare database in 1996, where an individual’s sex was recorded as female, and their date of birth was between 1973 and 1978.
  • 1989–95 cohort: participants were recruited online in 2012 and 2013, mainly from social media. Participants from this cohort were asked their sex in the 2013 survey. It is not known whether participants interpreted this to mean sex at birth or gender identity.
  • The gender identity of participants in the study is not known, as this information is not routinely collected. Participants in this study may identify as female or have a different gender identity.
National Hospital Morbidity Data/National Non-admitted Patient Emergency Department Database
  • Hospitalisation and emergency department presentation data are based on hospital admissions records. Patients' sex was recorded as 'male', 'female' or 'other'.
  • Depending on the practices of the hospital, this may be based on what the patient selected, or how hospital staff completed the record. It may also be based on an existing hospital record for the patient, which may no longer reflect how they identify.
  • It is important to note that it is not known if the people completing these records interpreted sex to mean sex at birth or gender identity.
  • A small number of hospitalisations/ED presentations (<10) were reported with a sex of ‘male’ or ‘other’. To preserve confidentiality, data presented in this report have been restricted to hospitalisations/ED presentations with a sex of ‘female’ only. The Estimated Resident Population for Australian females is used for the denominator when calculating rates.