An ovarian cyst is a fluid-filled sac that forms on or in an ovary, which is part of the female reproductive system. These are often benign, develop as part of the normal menstrual cycle, and usually disappear on their own within a few months. While most are harmless, they can sometimes cause problems if they are persistent, grow large, rupture, or twist. Types and causes Functional cysts are These are the most common type and are a normal part of the menstrual cycle. Follicular cysts is Form when a follicle , which holds the egg ., doesn't release its egg and continues to swell with fluid. Corpus luteum cysts is Form after an egg is released, when the follicle closes back up and fills with fluid. Pathological cysts is These are less common and can be caused by other conditions. Endometriomas Grow from endometrial tissue. Dermoid cysts Can contain tissue like hair, teeth, or bone and develop from cells that are present from birth. Polycystic Ovarian Syndrome Individuals with PCOS may have many small cysts on the ovaries, which are usually harmless follicles and don't need removal. Symptoms Most ovarian cysts are asymptomatic. When symptoms occur, they can include Bloating or a feeling of fullness in the abdomen Sudden, sharp pain in the lower abdomen Abdominal pain during exercise or intercourse When to seek medical attention Contact a healthcare provider , gynaecologist for any sudden, severe abdominal or pelvic pain. Seek emergency medical care if you experience pain accompanied by nausea and vomiting, as this could be a sign of a twisted ovary (torsion), which requires immediate surgery See a gynaecologist if you have a persistent or large cyst or one that causes symptoms, as it may require treatment