What are Uterine Fibroids

Fibroids are non-cancerous tumours that grow in the uterus (womb).

They are made up of muscle fibre. They can be as small as a pea and can grow to become as large as a pregnancy at term. It is estimated that by the age of 50 years, 70-80% of black women will have a fibroid or fibroids, while the incidence in white women is 60-70%.

They are rare in women under the age of 20, cause most symptoms in women in their 30s and 40s, and tend to shrink after the menopause.

It is not known exactly why fibroids form, but the female hormone oestrogen undoubtedly influences the growth of these tumours. This explains why they appear during a woman’s middle years (when oestrogen levels are high) and stop growing after the menopause (when oestrogen levels drop).

Uterine fibroids are nine times more common in black women than in white women. They also appear earlier and are often more numerous and grow to larger sizes in black women. The reason for this racially difference is unknown. There also appears to be a relations to weight, with women who weigh over 70kg being more likely to have uterine fibroids. It is thought that this relates to the higher levels of oestrogen in heavier women. (..further reading Fibroid Research)

It would be tempting to suppose that the contraceptive pill could increase the risk of uterine fibroids. While this could have been true several decades ago when the combined pill contained high levels of oestrogen, recent research suggests that the newer combined pill (with much lower oestrogen levels) and the mini pill (progestogen only) may actually help prevent or slow the growth of fibroids.

Further Reading

Fibroid Symptoms

Uterine Fibroids FAQ – Women’s Health Clinic

For an NHS appointment please ask your GP to refer you to the
Myoma Clinic, St George’s Hospital.

If seeking a private consultation please ring 020 8947 9877.

St George’s Fibroids Clinic London | Parkside Hospital Fibroids Clinic Wimbledon
Princess Grace Hospital Fibroids Clinic | St Anthony’s Hospital Fibroids Clinic


  • Women's Health – Women’s Health Clinic Website, Dedicated to Gynecological Disorders. Information on a wide range of women’s health disorders & symptoms women may experience.