Why endometriosis pain can continue after treatment

Treatment for endometriosis can bring relief, but some women continue to have pelvic pain even after hormone treatment or surgery. For those who have spent years seeking help, continuing pain can be distressing and difficult to understand. Why does this happen? Sometimes endometriosis remains or returns. But pain can also involve other conditions, and changes in how the nervous system responds to signals from the body. Understanding these different contributors can help guide further treatment. Endometriosis affects an estimated one in ten women of reproductive age worldwide. It happens when tissue similar to the lining of the womb grows elsewhere in the body, commonly around the pelvic organs. This can cause inflammation, the body’s response to injury or irritation, and scar tissue. Symptoms can disrupt working life and intimate relationships. A study across ten countries found that women with endometriosis lost working time through absence and reduced ability to work effectively while at their jobs. Interviews with women experiencing endometriosis-related sexual pain also described avoiding sex and strain on relationships. Treatments include painkillers, hormone medicines and surgery to remove areas of endometriosis, but symptoms can persist or return. The extent of endometriosis does not reliably predict pain severity. A study of 1,054 women undergoing surgery found only a weak and inconsistent relationship between disease stage, a classification of its extent, and the severity of pelvic pain symptoms. This helps explain why the amount of endometriosis found cannot, on its own, tell doctors how much pain someone experiences. What treatment can and cannot address Hormone treatments can help control endometriosis-related pain. Different medicines work in different ways, including suppressing the monthly cycle or reducing the production or effects of oestrogen, a hormone that encourages endometriosis tissue to grow. However, reducing the activity of endometriosis lesions may leave other sources of pain untreated. Surgery aims to remove or destroy areas of endometriosis. It can help, but it cannot guarantee that pain will disappear. Disease may remain after an operation or return later, and removing endometriosis does not necessarily address every contributor to pain. One example is adenomyosis, where tissue from the womb lining grows into the womb’s muscular wall. It can cause painful periods and heavy bleeding, and can occur alongside endometriosis. An operation to remove endometriosis outside the womb does not usually treat adenomyosis within it. Medicines can help manage adenomyosis symptoms; removing the womb, an operation called a hysterectomy, may be considered when other treatments have not helped. Even then, pelvic pain may continue if other causes remain. The muscles around the pelvis and bowel dysfunction can also contribute. The pelvic floor is a group of muscles supporting organs such as the bladder and bowel. Pain involving these muscles or the abdominal wall and a study of 210 women showed bowel pain to persist after surgery or hormone treatment and they may need assessment and treatment even after endometriosis has been removed. How the nervous system can change There is another part of the explanation: the way the nervous system processes signals. Persistent pain can involve changes that make the nervous system more sensitive. Signals that would not normally hurt may become painful, and painful signals may feel stronger. Increased sensitivity in the brain and spinal cord is known as “central sensitisation”. In a study of 520 women, at least one in four with endometriosis also had another long-term pain condition, such as fibromyalgia, which can make pain persist even after treatment through central sensitisation. These changes can help explain why pain continues after treatment, alongside any remaining disease or other painful conditions. They are physical changes in pain processing, and the resulting pain is real. A study of 239 patients undergoing endometriosis surgery found that higher scores on a questionnaire assessing symptoms associated with central sensitisation were linked to worse pain after surgery, even after accounting for pain levels beforehand. Pain improved overall in the study. However, the findings suggest that assessing sensitivity-related symptoms could help doctors discuss the possibility of continuing pain and plan additional care. The questionnaire does not directly measure changes in the nervous system or prove what causes an individual’s pain. What more comprehensive care looks like Continuing pain deserves further assessment. Doctors may need to consider whether endometriosis remains or has returned, alongside other conditions and changes in pain processing. Care may involve professionals from different specialties working together, often called a “multidisciplinary approach”. A gynaecologist, a doctor specialising in the reproductive system, can assess endometriosis and related conditions. A pelvic health physiotherapist can assess painful or persistently tense muscles, while a pain specialist can review options for managing ongoing symptoms. Psychological support can help someone manage the distress, disrupted sleep and effects on daily life that accompany persistent pain. Bowel or urinary specialists may also be involved where symptoms or disease require their expertise. The combination should reflect the person’s needs. In 2025, a review compared care involving several specialties with treatment from one discipline. It found that broader care may reduce pain and improve sexual function in women with chronic pelvic pain, although limitations in the evidence mean the findings remain uncertain. Treating endometriosis can be an important part of relieving pelvic pain. When symptoms continue, the next step is to investigate what else may be contributing and agree a treatment plan that addresses those findings, while taking the woman’s experience seriously.