The five-year randomized clinical trial will compare two treatments for fibroids – benign growths in the womb sometimes causing swelling of the stomach, severe discomfort and heavy menstrual bleeding.

Fibroids can grow if left untreated and can reduce the chances of a woman becoming pregnant. Hysterectomy is the most complete solution but means women can no longer conceive. Most women resist such radical and irreversible surgery.

Professor Klim McPherson of Oxford’s Nuffield Department of Obstetrics and Gynaecology is leading the study. He said: “Increasingly, women are delaying starting their families to an age when fibroids are more common.

“Women with fibroids are caught in the dilemma of needing the growths treated but possibly wanting to have children in the future and certainly not wanting to foreclose the opportunity by having a hysterectomy. So for a long time doctors and researchers have been trying to find ways of getting rid of fibroids while retaining a woman’s fertility.”

The study will compare the quality of life for women undergoing two different treatments; one removes the fibroids surgically – a myomectomy – the other blocks the blood supply to the growth by embolization – the insertion of a harmless substance which blocks the fibroid’s blood supply. ‘Women with fibroids want to know which of these procedures will provide the best chance of subsequently allowing pregnancy.”

About 80% of women aged 45-50 have fibroids but more than half of those women will not suffer symptoms. the growths are caused by changes to hormones as women age and can grow to ‘the size of a baby,’ Professor McPherson said. ‘Expelling a fibroid after embolization is sometimes as bad as having a baby and is much less pleasant.”

The £2m trial, funded by the NHS’s Health Technology Assessment Program, will study a sample of 800 women with fibroids who do not want hysterectomies. Half will be allocated randomly to one treatment and half to the other. the will be studied by gynaecologists and radiologists in around 15 centres across the UK.

The study is due to start this spring and will involve experts from Oxford, the universities of Glasgow and Birmingham, St. George’s Hospital, London and the charity Fibroid Network.

“No-one knows which treatment is best for quality of life or fertility but the treatments are very different and this trial should provide the answer. Women want to know which will give them the highest chance of conceiving a normal baby afterwards,’ Professor McPherson added.