Ovarian cysts are common, fluid-filled sacs that develop on or within an ovary. Many women experience them, and they are often harmless, resolving on their own. These cysts are a natural part of the female reproductive system’s function, particularly during childbearing years. Understanding their typical sizes and when size indicates a need for medical attention is important.
Understanding Typical Ovarian Cyst Sizes
Ovarian cysts vary significantly in size, from a few millimeters to several centimeters. Most functional ovarian cysts, the most common type, typically measure less than 5 centimeters in diameter and often resolve without intervention. Follicular cysts, a type of functional cyst, form when a follicle does not release an egg and continues to grow, usually measuring larger than 2.5 cm. Corpus luteum cysts, another functional type, form after an egg is released and the follicle seals off, often growing to about 3 cm, though they can reach up to 10 cm.
While functional cysts are generally small, other types can reach larger dimensions. Dermoid cysts (teratomas) can contain various tissues like hair or skin and often measure 10 cm or less, though they can grow larger. Cystadenomas, which develop on the ovary’s surface, can range from 1 to 3 cm but may become quite large, sometimes up to 30 cm. Endometriomas, or “chocolate cysts,” are filled with old menstrual blood and are associated with endometriosis.
Factors Affecting Ovarian Cyst Size
The type of cyst is a primary determinant of its size. Functional cysts, linked to the menstrual cycle, are typically smaller. Pathological cysts, not directly tied to the menstrual cycle, can grow larger and may require more attention.
Hormonal fluctuations also play a significant role in the development and size of functional cysts. For example, fertility medications can lead to multiple large follicular cysts. Pregnancy can also influence cyst size, as the follicle formed during ovulation may remain and enlarge throughout gestation. Individual variations in ovarian response and conditions like endometriosis can further affect how large a cyst becomes.
When Ovarian Cyst Size Becomes a Concern
While many ovarian cysts are small and asymptomatic, their size can become a concern. Cysts larger than 5 to 10 cm are more likely to cause symptoms or complications. These symptoms include pelvic pain, a feeling of fullness, pressure, or bloating in the abdomen. Pain during intercourse or difficulty with bowel movements or urination can also occur.
Larger cysts increase the risk of complications. Ovarian torsion, where the ovary twists on its blood supply, is more likely with cysts 5 cm or larger and can cause sudden, severe pelvic pain, nausea, and vomiting. Rupture is another potential complication, especially with larger cysts, leading to severe pain and internal bleeding. While most cysts are benign, the likelihood of a cyst being cancerous, though rare, increases with size, particularly in postmenopausal individuals.
Diagnosis and Management of Ovarian Cysts
Ovarian cysts are often discovered incidentally during a routine pelvic exam or imaging tests. A pelvic ultrasound is the most common diagnostic tool, allowing healthcare providers to visualize the cyst’s size, location, and whether it is fluid-filled or solid. An MRI or blood tests, such as a CA125 test, may be used if there are concerns about the cyst’s nature.
Management depends on factors like size, appearance, and symptoms. For small, asymptomatic cysts, a “watchful waiting” approach is often recommended, involving monitoring with follow-up ultrasounds to see if the cyst resolves. Many functional cysts disappear within a few menstrual cycles. If a cyst is large, persistent, or causing significant symptoms, medical management or surgical intervention may be considered. Surgery may involve removing just the cyst (cystectomy) or, in some cases, the entire ovary (oophorectomy).