An ovarian cyst is a fluid-filled sac on a woman’s ovary. Most ovarian cysts are functional cysts, meaning they form during the normal process of ovulation. Each month, an ovary releases an egg. The egg grows inside a follicle—or sac. Normally, the follicle ruptures to release the egg. Sometimes, the sac continues to grow, forming a follicular cyst. After the follicle releases an egg, it shrinks into a small mass. This is a corpus luteum. The corpus luteum temporarily helps make hormones in anticipation of pregnancy. Sometimes, it doesn’t shrink and forms a cyst instead. This is a corpus luteum cyst. Most ovarian cysts do not cause symptoms. When symptoms develop, they can include bloating, pressure in the abdomen, or pain on one side of the lower abdomen. The pain ranges from dull to sharp and may worsen with certain activities, such as sex or bowel movements. It may also come and go. Nausea, vomiting, and menstrual irregularities may also occur. See your doctor if you have any of these symptoms for a diagnosis. What are the risk factors for ovarian cysts? The main risk factor for developing an ovarian cyst is being a premenopausal woman with regular periods. Ovarian cysts are very common in women of childbearing age. They are so common that most women develop at least one small cyst each month. Most of these resolve without ever causing a problem. Sometimes, they cause symptoms that prompt a woman to seek medical care. Ovarian cysts are less common once a woman reaches menopause. What are the potential complications of ovarian cysts? In general, complications are rare for small functional ovarian cysts. They typically do not interfere with your ability to get pregnant. The majority of them resolve on their own without complications within weeks or months. Complications are more common with cysts that rupture, bleed, or are very large. Large cysts may cause the ovary to twist, resulting in severe pain. Is there a link between ovarian cysts and ovarian cancer? Ovarian cysts are usually noncancerous. In fact, it is rare to have a cancerous ovarian cyst, especially in premenopausal women. Cancerous cysts—or ovarian cancer—are more likely to occur in older women and the risk increases with age. Having an ovarian cyst is not a risk factor for ovarian cancer. However, women with polycystic ovarian syndrome (PCOS) may have a higher risk of developing the disease. Scientists are still studying a possible link between PCOS and ovarian cancer. See your doctor if you are concerned about your risk of ovarian cancer. Your doctor can review your medical history and help you understand your risk factors. You should also visit your doctor if you have symptoms of an ovarian cyst that persist for more than two weeks.