For most of her life, Carys Thurlby thought severe pain was normal.

The 43-year-old from Worcester, England, believes she had endometriosis from her first periods as a teenager, the BBC reported. She remembers sitting her school exams "chewing on paracetamol" as pain spread through her pelvis and legs.

"I didn't really know that being in so much pain each month was not normal," she said.

She was diagnosed at 19 after a laparoscopy, a keyhole surgery, during a bout of "excruciating" pain. "That was the first time I had ever heard of it," she said.

Endometriosis is a long-term condition in which tissue similar to the lining of the womb grows elsewhere in the body, usually in the pelvis, causing intense pain, the Daily Mail reported. It affects about 1.5 million women in Britain. There is no cure.

Over the years, Thurlby had several operations, but the relief never lasted. Her ovaries were removed after being damaged by the disease. She later had a hysterectomy, surgery to remove the womb.

That finally brought lasting relief. She has since lost 10 stone, about 140 pounds, in 18 months. "Having intense pain had become my normal," she said. The change has been "night and day."

She said chronic pain and fatigue had affected every part of her life as she raised her children and worked.

Doctors say a hysterectomy is not right for everyone with endometriosis. It ends the ability to have children and does not always cure the pain. Treatment can also include hormone therapy and surgery to remove the tissue.

Women with severe period pain are urged to see a doctor.

What we know: Carys Thurlby says a hysterectomy ended decades of endometriosis pain.
What we don't: Whether surgery would help other patients the same way, since a hysterectomy is generally considered a last resort.