Uterine fibroids are non-cancerous tumours that grow from the muscle layers of the womb. These benign growths of smooth muscle can vary from the size of a bean to being as large as a melon.
They are also known as leiomyomas and myomas. Fibroids affect around 30 percent of all women by the age of 35 years and from 20 to 80 percent by the age of 50 years.
They usually develop between the ages of 16 to 50 years. These are the reproductive years during which oestrogen levels are higher.
TYPES OF FIBROIDS
This is the most common type. An intramural fibroid is embedded in the muscular wall of the womb.
These fibroids extend beyond the wall of the womb and grow within the surrounding outer uterine tissue layer. They can develop into pedunculated fibroids, where the fibroid has a stalk and can become quite large.
This type of fibroid can push into the cavity of the womb. It is usually found in the muscle beneath the inner lining of the wall.
Cervical fibroids take root in the neck of the womb.
These may include:
- Heavy, painful periods, also known as menorrhagia
- Anaemia from heavy periods
- Lower backache or leg pain
- Frequent urination
- Pain during intercourse, known as dyspareunia
Other possible symptoms include:
- Labour problems
- Pregnancy problems
- Fertility problems
- Repeated miscarriages
If fibroids are large, there may also be weight gain and swelling in the lower abdomen. Once a fibroid develops it can continue to grow until menopause. As oestrogen levels fall after menopause the fibroid will usually shrink.
During the reproductive years, oestrogen and progesterone levels are higher. When oestrogen levels are high, especially during pregnancy, fibroids tend to swell. They are also more likely to develop when a woman is taking birth control pills that contain oestrogen.
Genetic factors are thought to impact the development of fibroids.
There is also evidence that being overweight or obese increases the risk of fibroids.
Childbearing lowers the risk of developing fibroids. The risk reduces each time a woman gives birth.
Diagnostic tests can detect fibroids and rule out other conditions:
- MRI – to determine the size and quantity
- A hysteroscopy – small device with a camera attached to the end to examine the inside of the womb. The device is inserted through the vagina and into the womb through the cervix. The doctor can also take a biopsy at the same time to identify potentially cancerous cells in the area.
- A laparoscopy may also be performed. The doctor will make a small opening in the skin of the abdomen and inserts a small tube with a lighted camera attached through the layers of the abdominal wall. The camera reaches into the abdominopelvic cavity to examine the outside of the womb and its surrounding structures. A biopsy can be taken from the outer layer of the womb.
Treatment is only recommended for those women experiencing symptoms as a result of fibroids. If the fibroids are not affecting quality of live treatment may not be necessary.
Fibroids can lead to heavy periods but if these do not cause major problems you may choose not to have treatment.
Treatment can take the form of medication or surgery and this will depend on the location of the fibroids, the severity of the symptoms and any future childbearing plans.
The first line of treatment for fibroids is medication.
A drug known as a gonadotropin-releasing hormone agonist (GnRHa) causes the body to produce less oestrogen and progesterone. This will shrink the fibroids. GnRHa stops the menstrual cycle without affecting fertility.
GnRH agonists can cause menopause-like symptoms, including hot flashes, a tendency to sweat more, vaginal dryness and in some cases a higher risk of osteoporosis.
Other drugs may be used and these include:
Non-steroidal anti-inflammatory drugs (NSAIDs)
Anti-inflammatory medications reduce the production of hormone like lipid compounds called prostaglandins. Prostaglandins are associated with crampy periods and they are thought to be associated with heavy menstrual periods. NSAID may be effective at reducing fibroid pain but it does not reduce bleeding from fibroids and it does not affect fertility.
Birth control pills
Oral contraceptives help regulate the ovulation cycle and they may help reduce the amount of pain or bleeding during periods.
Levonorgestrel intrauterine system (LNG-IUS) – Mirena
This is a plastic device placed inside the womb. It releases a hormone call levonorgestrel over an extended timeframe. The hormone stops the inside lining of the womb from growing too fast which reduces menstrual bleeding. Adverse effects include irregular bleeding, for up to 6 months or longer, headaches, breast tenderness and acne. In some cases, your periods can stop.
Severe fibroids may not respond to more conservative treatment options and surgery may then be necessary.
This is the partial or total removal of the womb. This treatment is considered for large fibroids or excessive bleeding.
This is the removal of fibroids from the muscular wall of the womb. It can help women who still want to have children.
Removing the lining inside of the womb may help if fibroids are near the inner surface of the womb.
Complications may include:
Menorrhagia – also called heavy periods
This can sometimes prevent a woman from functioning normally during menstruation leading to depression, anaemia and fatigue.
If fibroids are large, swelling and discomfort may occur in the lower abdomen. They may also cause constipation with painful bowel movements.
Preterm birth, labour problems and miscarriages may occur as oestrogen levels rise significantly during pregnancy.
Fibroids can make it harder for the fertilized egg to attach itself to the lining of the womb. A submucosal fibroid growing on the inside of the uterine cavity may change the shape of the womb which makes conception more difficult.
This is a rare form of cancer that is thought to be able to develop inside of a fibroid in very rare cases.
Other serious complications include acute thromboembolism, deep vein thrombosis (DVT), acute renal failure and internal bleeding.
FIBROIDS AND FERTILITY
Approximately 5% – 10% of infertile women have fibroids. Their size and location determines whether fibroids affect fertility. Examples include fibroids that are inside the uterine cavity (submucosal) or very large (>6 cm in diameter) within the wall of the uterus (intramural).
How do fibroids cause infertility?
There are several ways uterine fibroids can reduce fertility:
- Changes in the shape of the cervix can affect the number of sperm that can enter the uterus.
- Changes in the shape of the uterus can interfere with the movement of the sperm or embryo.
- Fallopian tubes can be blocked by fibroids.
- They can impact the size of the lining of the uterine cavity.
- Blood flow to the uterine cavity can be affected. This can decrease the ability of an embryo to stick (implant) to the uterine wall or to develop.