Endometriosis affects nearly 200 million women, yet diagnosis often takes years
Tissue resembling the womb's lining can take root on the ovaries, bowel, bladder and occasionally even the lungs. Endometriosis affects roughly one in ten women of reproductive age, around 200 million people, but the average wait for a diagnosis runs from 5 to 12 years, and many are told their pain is normal.
The lesions behave like the lining they mimic. They shed tissue each cycle, but it has nowhere to go, so it lingers, inflames the area and can knit organs together with fibrous bands called adhesions. Some lesions stay on the membrane lining the abdomen; others burrow more than 5 millimetres deep into the bowel or bladder wall. Ovarian cysts filled with old blood look so dark brown they are nicknamed chocolate cysts.
Severity and pain are only loosely linked. A woman with small patches may suffer badly while someone with extensive disease feels little. Pain usually peaks during periods and may be described as clawing or stabbing. About a quarter of those diagnosed have fertility problems, and the World Health Organization attributes 4.8 percent of female infertility to the disease. When it reaches the pleura around the lungs, it can cause a lung to collapse in time with the menstrual cycle, most often on the right side.
The cause remains uncertain. The leading theory is retrograde menstruation, in which blood flows backwards through the fallopian tubes into the pelvis. Supporting this, only animals that shed their lining, such as baboons and rhesus monkeys, develop the condition naturally. Yet almost every woman has some backward flow and only about 10 percent develop the disease. Studies assign roughly half the risk to genes, with 80 genetic regions linked so far; a close relative with it raises the odds three- to nine-fold. Endocrine-disrupting chemicals such as dioxins and bisphenol A may add to the risk.
A presumed diagnosis can come from symptoms and imaging, but keyhole surgery with a biopsy confirms it. There is no cure. Hormonal treatments, painkillers and surgery can ease symptoms, though lesions return after surgery in a substantial minority. Endometriosis is also associated with pregnancy complications, including a three-fold higher risk of placenta previa, and with heart disease and stroke in cohort studies.
Source: Endometriosis
