Uterine fibroids are benign tumors that present in the uterus of a woman. The variance in size and shape for each woman affected by the condition can be notable. Additionally, the fibroids can form in several different areas of the uterus.
The location of the benign tumors can be used as a categorization system to group different types of fibroids according to which area of the uterus they affect.
Intramural fibroids refer to benign tumors that occur in the endometrium, the lining of the uterus wall. This is the most common type, accounting for 70% of uterine fibroids and affect one in four of all women of childbearing age.
Usually they begin as small nodules on the wall of the uterus, which may grow and extend into the womb with time. In some cases, they may grow considerably in size, causing distortion of the uterine cavity and the womb to become stretched.
Rarely, women with intramural fibroids may result in infertility, for approximately 1 in 30 women with uterine fibroids. This is thought to occur because the fibroids obstruct the passage of sperm into the uterine cavity, which is more likely to occur if they are located close to the cervix. It can also affect the implantation of the embryo and fetus development due to possible distortion of the uterine cavity.
Subserosal fibroids refer to benign tumors that develop outside the uterus on the serosa. The growths usually extend outwards, resulting in a knobby appearance of the uterus when examined with imaging techniques. This type is relatively common among women of childbearing age but does not typically affect the shape or size of the uterine cavity, as they grow externally.
The symptoms associated with subserosal fibroids are usually less pronounced than other types of fibroids and their presence is not thought to be related to infertility. However, in some cases they may compress the fallopian tubes, resulting in infertility. They may have a significant impact on pregnancy when large in size, as they increase pressure on the surrounding organs.
If a woman experiences bothersome symptoms as a result of subserosal fibroids, surgical removal of the fibroids is usually the best treatment. A laparoscopy is the most commonly used surgery, as it provides easy access to the area for the fibroid removal.
Pedunculated fibroids refer to a tumor that develops a long stem that supports the tumor as a type of base. Other types of fibroids, such as subserosal or submucosal, may become pedunculated if they grow in a stem-like fashion to extend either inside or outside of the uterus.
This type is more likely to cause symptoms of pain in the pelvic or abdominal area, due to the obstruction of the uterus and surrounding organs.
Submucosal fibroids are formed on the inner side of the uterus in the submucosal layer. This type is less common than other types of fibroids, accounting for approximately 1 in 20 cases of uterine fibroids in women.
They often begin as intramural fibroids and grow toward the endometrial cavity to obstruct the submucosal layer. When small in size, there may not be significant symptoms but some women notice particularly heavy bleeding during menstruation and increased abdominal pain.
It is also possible for submucosal fibroids to result in infertility. This can occur due to obstruction of the fallopian tubes or affecting the size and shape of the uterus cavity. They also adversely affect the ability of the uterus to contract, which interferes with the transport of sperm and ovum. If present during pregnancy, they are also likely to grow in size and increase the risk of miscarriage and congenital deformities. If causing significant symptoms, the fibroids can be removed with a surgical procedure.