Intramural fibroids are noncancerous growths that develop within the muscular wall of the uterus. They are one of the most common types of uterine fibroids and can vary in size from very small to large enough to affect the shape of the uterus. Some women may experience symptoms such as heavy menstrual bleeding, pelvic pain, bloating, frequent urination, or lower back discomfort, while others may have no symptoms at all. Hormonal changes often influence fibroid growth.