Uterine fibroids are benign muscular growths that can develop inside or outside the uterus, usually in women in their childbearing years. They are also called leiomyomas or myomas.
Fibroids are almost always benign in nature and are extremely common – almost 40 to 60% women get fibroids by the age of 35, and 60-80% by the time they turn 50. They can be found as a single growth or in clusters. The size of a single fibroid can vary greatly – from 1 mm (a coin) to 8 inches in diameter in size – for perspective, a uterus is usually 4 inches in diameter, so a fibroid that big can distend your belly and cause discomfort.
How uterine fibroids are detected?
Most fibroids are detected in a routine pelvic examination. However, this usually happens when their size is large enough to be palpated during bimanual examination, and smaller fibroids go undetected for long periods of time, especially if they cause no symptoms.
An ultrasound, MRI, hysteroscopy and saline-infused sonography can be taken as further tests to confirm their presence.
Types of uterine fibroids
Fibroids are classified based on the area of the uterus they grow in, and it’s possible to have more than one type at the same time:
- Intramural fibroids: The most commonly found type of fibroids, these fibroids grow within the walls of the uterus. The more they grow in size, the more they can stretch the uterus.
- Subserosal fibroids: These fibroids grow outside the uterus and can put outward pressure on the surrounding organs, as they grow in size.
- Submucosal fibroids: These are the rarest form and grow in the submucosa layer – the layer just underneath the uterine lining, and can bulge inwards into the uterus, and cause cramping and bleeding.
- Depending on how deep the fibroid lies in the uterine wall they are classified by FIGO as type 1 and type 2.
- Pedunculated fibroids: Some subserosal and submucosal fibroids grow on slim muscular stems, called stalks, that support the fibroids. In that case, they’re known as pedunculated fibroids. Submucosal pedunculated fibroids are classified by FIGO as type 0 fibroid.