About 1 in every 9 women in Australia are diagnosed with endometriosis by their 40s, according to a report by the Australian Institute of Health and Welfare.

More than 34,000 hospitalizations related to the condition were registered between 2016 and 2017.

These findings were published in the report Endometriosis in Australia: prevalence and hospitalisations, based on endometriosis data obtained by researchers from The University of Queensland (UQ).

“Numbers like this show how relatively common the condition is — it’s something likely to affect a significant amount of women throughout their lifetime,” Ingrid Rowlands, PhD, a UQ School of Public Health researcher involved in the study, said in a press release.

“Endometriosis has been under-recognised in both the social and medical communities — many people do not know what it is, and doctors find it challenging to treat and manage patients who present with symptoms.”

Endometriosis causes cells that usually line the uterus to grow elsewhere in the body, including in the ovaries, fallopian tubes, peritoneum (the membrane lining the abdominal and pelvic cavities), and the outside of the uterus.

Similar to the normal uterine lining, this tissue responds to hormonal cycles, causing periods of bleeding. This results in inflammation and scarring that may be accompanied by severe pain, heavy bleeding, and infertility, altogether taking an emotional toll on patients.

Even though some women may be asymptomatic, with no pain or discomfort, others can experience very disabling symptoms.

“Some women might not be able to get out of bed because their symptoms are so severe — they may experience acute pain, irregular bleeding and bowel upsets,” Rowlands said.

The report focused on the prevalence of endometriosis based on data from the Australian Longitudinal Study on Women’s Health (ALSWH), which includes two groups of women —  those born in 1973–78, and those born in 1989–95.

Researchers at UQ used data of women said to have been diagnosed with endometriosis, and linked this information with Medicare and subsidized medicine claims, as well as hospitalization records, to determine prevalence.

The report found that 1 in 9 women born between 1973 and ’78 were diagnosed with endometriosis by the time they reached the of age 40 to 44. That’s about 11.1% of women in this age group in the country.

Moreover, in the period between 2016 and 2017, there were about 34,200 endometriosis-related hospitalizations — around 15 of every 1,000 hospitalizations among women ages 15 to 44 were related to endometriosis.

Most stays lasted two days or less, and most were partly or fully funded by private health insurance (57%). A further 35% were covered by public insurance, while 7.9% were self-funded.

Rowlands stressed that diagnosing endometriosis is often complex, which may explain why prior studies have underestimated its prevalence.

“Symptoms of endometriosis can also mimic other conditions like irritable bowel syndrome, so one of the greatest difficulties lies in diagnosis, which can only be made through surgery.”

Diagnostic hysteroscopy, a procedure used to examine the inside of the uterus, was the most common procedure undertaken by hospitalized women — done in 38% of endometriosis-related hospital stays.

“These findings highlight the importance of having accurate statistics and represent our first step in contributing to the National Action Plan on Endometriosis,” said Gita Mishra, PhD, professor at UQ and director of ALSWH.

“There were no up-to-date, accurate estimates on the number of Australian women living with the condition before now,” Rowlands said.

The report also calls attention to the lack of information on its overall prevalence in the general population. Its authors suggest that this data could be provided by asking women in a nationally representative survey if they were ever told by a health professional that they have endometriosis.

“We are trying to provide the best data we can to build on this action plan and to inform future healthcare policy and practice,” Rowlands added.

“This is a debilitating condition for some women, and it is so important to identify the number of women affected to move forward, assess their condition closely and help optimize outcomes.”