Generally the uterus is about the size of an egg, well contained in the pelvis if not pregnant, and cannot cause the abdominal wall to protrude.
Uterine fibroids are non-cancerous tumor growth. The muscle knots that comprise a fibroid uterus can be microscopically sized or very large.
The total weight of a woman's uterus in her fertile years is typically about 60-70 grams. This uterus was 768 grams, and shown here are the fibroids removed at the time of a laparoscopic hysterectomy. The largest uteri removed with laparoscopic are about 7 lbs or around 3200 grams. Just for comparison, you should know the pregnant uterus can swell to up to 1000 grams to accommodate it's contents! T
he fibroids themselves have a solid feel to them, almost as rigid as a rubber ball. For the most part the pressure the enlarged uterus can produce is uncomfortable, although some women report significant pain. The pressure of such a large uterus such as this one might produce actual deformities of neighboring organs or of the cervix itself.
Some women have enlarged uterus due to the lining glands getting entrapped within the muscle of the uterine wall, which is a condition called adenomyosis, and this can co-exist with the fibroids or be seen alone. The largest uterus ever reported with only adenomyosis was 475 grams.
A number of genetic code mistakes can lead to a woman getting uterine fibroids, and these genetic changes to the uterine cells likely affect the size of the uterus too. The fibroids seen here were not cancerous, although fibroids are actually uterine scarcomas which is a type of cancer.
There is no exact pattern to fibroid growth, and some swell to very large over months, and others can slowly change over years. In other women the fibroid can grow and then stabilize. But most fibroids will continue to grow until menopause is reached.
Speak to your gyno if you have abdominal selling, irregular bleeding, pelvic or bladder pressure symptoms, all these symptoms may be associated with fibroids that are making the uterine size enlarge. A simple ultrasound can measure and determine the size and location of uterine fibroid masses, although a CT scan may be better at determining if any significant problems from pressure due to the bulk of the uterus has occurred. Either way, it is important to consult with your gyno if you have a concern.