Fibroids are the most common non-cancerous tumour found in women of childbearing age. They develop in or around the womb, with around 1 in 3 women developing them at some point. They are most common in women aged 30-50: symptoms can include heavy or painful periods, lower back or abdominal pain, and pain or discomfort during sex.

Submucous fibroids can also reduce fertility, although it is unclear how. It is possible that a fibroid may prevent an embryo from implanting in the womb, but having fibroids does not mean you will have trouble conceiving. Fibroids that distort the uterine cavity by increasing the sheer bulk of the womb can contribute to early pregnancy loss. During pregnancy, such large fibroids can outgrow their blood supply and cause pain, as well as making the baby lie in an unusual way (malpresentation); this may make a caesarean section necessary.