SCIENTISTS in Liverpool may have solved the riddle of a womb complaint that affects millions of British women and can lead to infertility.
Endometriosis causes severe pain, heavy periods and can make sufferers infertile, yet the precise cause of the condition remains unknown.
Now scientists at the University of Liverpool have identified an enzyme that could be responsible for the condition, which results in patches of the womb’s inner lining growing in other parts of the body.
Around 15% of women of reproductive age have the complaint and half of infertile females are affected by it.
The research, published in the journal Human Reproduction, is expected to help scientists develop new techniques for diagnosing and treating the debilitating condition.
The enzyme, named Telomerase, is supposed to be released by cells in the inner lining of the womb early in the menstrual cycle, but in women affected by endometriosis it is produced later on as well.
This causes cells to continue replicating more than normal in the womb, dividing uncontrollably and acquiring the ability to spread and survive outside the uterus.
Dr Dharani Hapangama, who led the new research, said: "Women who have endometriosis express this enzyme in both the early and late stages of the menstrual cycle which means the cells will continue to divide and lose their focus in supporting the establishment of a pregnancy.
"As a result the lining of the womb may be more hostile to an early pregnancy, and the cells that are shed at this late stage in the menstrual cycle may be more aggressive and more able to survive and implant outside the uterus, causing pain in the pelvic or abdomen area."
In most cases endometriosis is diagnosed between the ages of 25 and 40.
The disorder can occur in several places in the body, most commonly the fallopian tubes, ovaries, bladder, the bowel, the intestines, the vagina and the rectum.
Endometriosis cells behave in the same way as those lining the womb, so every month they grow during the menstrual cycle and shed blood.
Normally before a period, the womb lining thickens in order to receive a fertilised egg. When pregnancy does not occur the lining breaks down and bleeds, producing a period.
Endometrial tissue anywhere in the body undergoes the same process of thickening and bleeding, but has no way of leaving the body.
The "trapped" tissue leads to swelling, pain and bleeding wherever it happens to be situated.
