Uterine fibroids are usually not dangerous. However, in rare cases, these growths can block or distort the fallopian tubes and complicate pregnancy.
Uterine fibroids, also known as leiomyomas, are normally benign. They occur when a cell in the muscular tissue of the uterus repeatedly divides and becomes a rubbery independent mass. According to the Mayo Clinic, three out of four women may develop these fibroids at some point during their lives, and many never experience any symptoms.
Uterine fibroids are not known to increase the risk of uterine cancer. They are also almost never cancerous. Although it is rare, it is possible for fibroids to alter the shape of the fallopian tubes. They can also cause changes to the menstrual cycle, such as heavy periods and anemia resulting from the substantial blood loss.