Fibroids Fibroids are non-cancerous growths of the womb. They can vary in size from a few millimetres to 20cm (eight inches) across, with the average size being around 2cm (three quarters of an inch). There are three main types of fibroid -- those found within the wall of the womb (intramural), those that grow from the outside of the wall into the pelvic cavity (subserosal) and those that grow from the inner wall of the womb into the womb itself (submuscosal). Their growth is usually slow and is thought to be stimulated by hormones. Symptoms Most women who have fibroids are unaware of them and suffer no symptoms. Often, they don't cause problems and may not need treatment. But you may experience some symptoms as follows: Heavy periods Prolonged periods or bleeding between periods Discomfort in the lower abdomen (if it is a large fibroid) The need to pass urine often if it is pressing on your bladder Constipation if it is pressing on your rectum Backache if it presses against your spine Pain or discomfort during sexual intercourse -- if it is growing in the womb near the vagina Severe pain if the fibroid is growing on a stalk and twists Pain and fever if it outgrows its blood supply and starts to degenerate, but this is rare Difficulty in getting pregnant -- this is very rarely a symptom of fibroids, they do not usually affect fertility Causes The cause of fibroids is still unknown. The hormones oestrogen and