The uterus is a hollow organ, about the size and shape of a medium-sized pear. The uterus is where a fetus grows and develops when a woman is pregnant. The uterus has 2 main parts (see picture above). The cervix is the lower end of the uterus that extends into the vagina. The upper part of the uterus is called the body or the corpus. (Corpus is the Latin word for body.) Although the cervix is technically part of the uterus, when people talk about the uterus, they usually mean the body, not the cervix.


The body of the uterus has 2 main layers. The inner layer or lining is called the endometrium. The outer layer of muscle is known as the myometrium. This thick layer of muscle is needed to push the baby out during birth. The tissue coating the outside of the uterus is the serosa.


Hormone changes during a woman’s menstrual cycle cause the endometrium to change. During the early part of the cycle, before the ovaries release an egg (ovulation), the ovaries produce hormones called estrogens. Estrogen causes the endometrium to thicken so that it could nourish an embryo if pregnancy occurs. If there is no pregnancy, estrogen is produced in lower amounts and more of the hormone called progesterone is made after ovulation. This causes the innermost layer of the lining to prepare to shed. By the end of the cycle, the endometrial lining is shed from the uterus and becomes the menstrual flow (period). This cycle repeats throughout a woman’s life until menopause (change of life).

What is Uterine Cancer?


The most common cancer of a reproductive system of a woman is known as uterine cancer. This cancer starts in cell layers that form the lining of the uterus. This cancer can be detected in its early stage as it causes abnormal vaginal bleeding. The surgical removal of the uterus can cure uterine cancer.