Millions of people living with endometriosis may face delays in diagnosis and treatment because healthcare guidelines in many countries fail to consider teenagers and the experiences of patients, a global study has found.

The study published in Nature, involving researchers from the World Health Organisation (WHO), senior board members of the World Endometriosis Society, and representatives from patient groups, reviewed endometriosis guidelines from 47 countries, including 19 published in languages other than English.

The findings revealed gaps in how the condition is diagnosed and treated, raising concerns about whether existing recommendations meet the needs of everyone affected.

About 70 per cent of the guidelines reviewed had not involved people living with endometriosis in their development. The researchers also found that many guidelines overlooked adolescents, despite symptoms often beginning during the teenage years.

“A significant proportion of guidelines did not involve people living with endometriosis in their development, particularly in developing countries with substantial gaps in Africa and the Eastern Mediterranean,” the researchers said.

Endometriosis is a long-term condition in which tissue similar to the lining inside the uterus grows in other parts of the body, including the ovaries, fallopian tubes and tissue around the pelvis. In some cases, it can also affect areas outside the pelvis.

The condition can cause severe pain, heavy menstrual bleeding and difficulties getting pregnant. It is estimated to affect about 190 million women and girls of reproductive age worldwide, or roughly one in 10. There is currently no cure, although treatment can help manage symptoms.

Common symptoms include severe period pain that interferes with daily activities, pain in the lower abdomen or back, heavy menstrual bleeding, pain during sex, pain when passing urine or stool, bloating, fatigue and difficulty becoming pregnant. Some people experience several symptoms, while others have few or none.

However, these symptoms can be mistaken for other health problems or dismissed as normal menstrual discomfort, making it difficult for patients to get the help they need.

Why diagnosis is often delayed

“One of the major challenges is that severe period pain is sometimes treated as a normal part of menstruation. Teenagers may be told to tolerate the pain or take painkillers without further investigation, even when symptoms repeatedly affect their school attendance, sleep and everyday activities,” the researchers said.

Some patients may also struggle to explain their symptoms or may not know that the pain they experience could be caused by a medical condition. Others may visit several healthcare facilities before finding a health professional who recognises the signs.

Endometriosis can also be difficult to diagnose because its symptoms resemble those of other conditions, including pelvic infections and some digestive or urinary problems. Diagnosis may require a detailed medical history, physical examination and imaging tests, such as an ultrasound or MRI. In some cases, further investigations may be necessary.

The researchers found that one-quarter of the guidelines reviewed had not included input from adolescents. This is particularly concerning because symptoms frequently begin during the teenage years, when early recognition could help patients seek care sooner.

Delays can leave people living with pain for years without knowing its cause. The condition may affect their ability to attend school or work, maintain relationships and carry out routine activities. For some, it can also create emotional stress and uncertainty about their future fertility.

Differences in care between countries

The researchers found considerable differences in recommendations for diagnosis, treatment, fertility care and non-medical ways of managing endometriosis. Most of the guidelines came from high-income countries, particularly in Europe, while some countries had no national guidelines at all.

This can create difficulties for patients and healthcare workers, especially in places where specialist services and diagnostic facilities are limited. Without clear guidance, recognising symptoms, deciding when to refer patients and providing appropriate treatment can become more challenging.

“Different countries face different challenges, including access to treatment, but minimum standardised guidelines are an important starting point in addressing healthcare inequities,” the researchers said.

The study also identified gaps in the involvement of general practitioners. However, gynaecologists contributed to all the international guidelines reviewed; fewer than half included input from general practitioners.

This matters because general practitioners are often the first health professionals patients consult when they experience painful periods or persistent pelvic pain. Recognising warning signs at this stage can help patients receive further assessment and treatment sooner.

The researchers said guidelines should be developed with greater involvement from patients, healthcare workers and other relevant groups. Including people who live with endometriosis could help ensure recommendations reflect the symptoms they experience, the challenges they face when seeking care and the treatments that help them manage the condition.

The findings also point to the need for greater awareness among teenagers, parents, and healthcare workers so that severe menstrual pain is not automatically dismissed as normal.

The WHO estimates that endometriosis affects 190 million women of reproductive age worldwide, or one in 10. In Kenya, studies at two Nairobi hospitals found the condition in 4.6 per cent and 6.8 per cent of women undergoing laparoscopic surgery, although the country lacks a reliable national prevalence estimate.