The uterus, or womb, is the main female reproductive organ. In women who are able to have children, the main function of the uterus is to nourish a developing foetus.
The uterus is about the size and shape of a hollow, upside-down pear. The bulk of the uterus is smooth muscle tissue, which is called the myometrium. The uterus sits low in the abdomen between the bladder and rectum and is held there lightly by muscle. It is joined to the vagina by the cervix, which is the neck of the uterus.
When women ovulate, or produce eggs in their ovaries, an egg travels through their fallopian tube into the uterus. If the egg is fertilised by a sperm, it will implant itself into the lining of the uterus and grow into a baby.
The lining of the uterus is called the endometrium. The endometrium is made up of several layers, including skin-like cells (surface epithelium), blood vessels, tissue spaces and glands. If a woman is ovulating, the endometrium will grow thicker each month to prepare for pregnancy. If the egg is not fertilised, the top layers of the endometrium are shed and flow out of the body through the vagina during menstruation. This is known as a woman’s period.
Menopause occurs when a woman no longer releases the hormones that cause ovulation and menstruation. A menopausal woman’s monthly periods stop, and she is no longer able to become pregnant. The uterus becomes smaller and the endometrium becomes thinner and inactive.
What is cancer?
Cancer is a group of many related diseases. All cancers begin in cells, the body’s basic building blocks.
Normally, cells grow and multiply in an orderly way.
However, damaged genes can cause them to behave abnormally. They may grow into a lump called a tumour. Tumours can be benign (not cancer) or malignant (cancer).
Benign conditions of the uterus (not cancer)
Fibroids are common benign tumours that grow in the muscle of the uterus. They occur mainly in women in their forties. Women may have many fibroids at the same time. Fibroids do not develop into cancer. As a woman reaches menopause, fibroids are likely to become smaller, and sometimes they disappear.
Usually, fibroids cause no symptoms and need no treatment. But depending on their size and location, fibroids can cause bleeding, vaginal discharge, and frequent urination. Women with these symptoms should see a doctor. If fibroids cause heavy bleeding, or if they press against nearby organs and cause pain, the doctor may suggest surgery or other treatment.
Endometriosis is another benign condition that affects the uterus. It is most common in women in their thirties and forties, especially in women who have never been pregnant.
It occurs when endometrial tissue begins to grow on the outside of the uterus and on nearby organs. This condition may cause painful menstrual periods, abnormal vaginal bleeding, and sometimes loss of fertility (ability to get pregnant), but it does not cause cancer. Women with endometriosis may be treated with hormones or surgery.
Endometrial hyperplasia is an increase in the number of cells in the lining of the uterus. It is not cancer. Sometimes it develops into cancer. Heavy menstrual periods, bleeding between periods, and bleeding after menopause are common symptoms of hyperplasia. It is most common after age 40.
To prevent endometrial hyperplasia from developing into cancer, the doctor may recommend surgery to remove the uterus (hysterectomy) or treatment with hormones (progesterone) and regular follow-up exams.
Malignant tumours (cancer)
A malignant tumour is made up of cancer cells. If these cells are not treated, they may spread beyond their normal boundaries and into surrounding tissues, becoming invasive cancer. This spread of cancer is called metastasis.
When cancer spreads from its original place to another part of the body, the new tumour has the same kind of abnormal cells and the same name as the primary tumour.