A uterine cyst is a fluid-filled sac that forms on or inside the uterus. It can be a normal part of the monthly menstrual cycle or it can occur as a result of illness or surgery. Cysts can also be a symptom of certain diseases, such as cancer or endometriosis.
Each month, during the monthly menstrual cycle, a follicle (cyst) grows on an ovary where an egg is developing. When the egg matures, it is released from the follicle during ovulation. This releases the sex hormones estrogen and progesterone. If a follicle fails to break open and release an egg, it may fill with fluid and become a cyst. This is called a functional cyst and it is a normal part of the menstrual cycle.
When a person has an ovarian cyst, the doctor may notice it on a pelvic exam or they may discover it during a blood test. Symptoms can include pelvic pain or unusual vaginal bleeding. Cysts are more common in women who have a family history of breast and ovarian cancer or who have endometriosis or fibroids.
Some people have a condition called polycystic ovary syndrome (PCOS), which often causes one or more cysts to form. PCOS can cause other health problems, such as irregular periods, infertility and abnormal vaginal bleeding. A person who has PCOS should talk to a doctor about getting a screening test for an ovarian cyst.
Most ovarian cysts are non-cancerous, but they can be difficult to diagnose because many of them don’t have symptoms. If they do have symptoms, they can include painful periods, heavy vaginal bleeding, bloating and abdominal pain or a feeling that something is stuck in the pelvis.
In most cases, doctors will ask about a person’s health history and do a pelvic exam. If a doctor notices an ovarian cyst, they will order tests to help them find out what kind of a cyst it is and what might be causing it. Tests include a pelvic ultrasound, which uses sound waves to view the growth and determine its size, shape and whether it’s solid or filled with fluid. They may also order a CT scan or magnetic resonance imaging (MRI), which use large magnets to create detailed images of the ovary.
Some cysts are caused by medications, such as birth control pills. When this happens, the doctor may give the patient a prescription for birth control pills to stop ovulation. This does not make the cyst go away but it can prevent new ones from forming. If a cyst does not get smaller or the symptoms don’t improve, other tests may be needed, such as laparoscopy. This is a procedure where the doctor inserts a thin instrument with a camera into the abdomen through a small cut. The doctor can then take a closer look at the cysts and remove them if necessary.