What causes cancer of the womb?

The exact cause of cancer of the womb is not yet known.

Women who are still having periods and who take the contraceptive pill are believed to have a lower risk of developing cancer of the womb. Women who have had their menopause and who take oestrogen-only HRT (hormone replacement therapy) for a long time may have a slightly increased risk of developing the disease. Women who have not had their womb removed and are taking HRT should make sure that they are taking a combination of the hormones oestrogen and progesterone, rather than oestrogen on its own. Taking combined oestrogen and progesterone HRT for up to five years causes no increase in the risk of developing cancer of the womb, but if it is taken for more than five years the risk may be slightly increased.

The use of tamoxifen (a hormonal therapy sometimes taken to treat breast cancer) over a long period of time also slightly increases the risk of developing cancer of the womb. However, this is so slight that the benefits of taking tamoxifen to treat breast cancer are considered to outweigh the risk.

Cancer of the womb most commonly occurs in women between the ages of 50 and 64. It rarely affects women under 50.

Womb cancer, like other cancers, is not infectious and cannot be passed on to other people. Cancer of the womb is not caused by genetic changes that can be passed down through families, so it is not inherited.