Most women don't experience any symptoms of fibroids, but they can cause significant problems in rare cases.
The likelihood of complications occurring depends on factors such as the position of the fibroids and their size.
Some of the main complications are outlined below.
If fibroids are present during pregnancy, it can sometimes lead to problems with the development of the baby or difficulties during labour.
Women with fibroids may experience tummy (abdominal) pain during pregnancy, and there's a risk of premature labour.
If large fibroids block the vagina, a caesarean section (where the baby is delivered through a cut in the tummy and womb) may be necessary.
In rare cases, fibroids can cause miscarriage (the loss of pregnancy during the first 23 weeks).
Your GP or midwife will be able to give you further information and advice if you have fibroids and are pregnant.
Infertility (the inability to become pregnant) may occur in cases where a woman has large fibroids.
Fibroids can sometimes prevent a fertilised egg attaching itself to the lining of the womb, or prevent sperm reaching the egg, but this is rare.
If you have a submucosal fibroid (a fibroid that grows from the muscle wall into the cavity of your womb), it may block a fallopian tube, making it harder for you to become pregnant.
The fallopian tubes connect the ovaries (where the egg is released) to the womb.