Follicular cysts are the most common type of functional ovarian cyst, representing a fluid-filled sac that forms on the ovary. They are a normal occurrence for individuals during their reproductive years and are generally considered benign. These cysts are closely related to the hormonal fluctuations of the menstrual cycle and are a byproduct of the ovulation process. They are usually temporary and often resolve on their own without medical intervention.
How Follicular Cysts Form
The female reproductive cycle involves the monthly development of small, fluid-filled sacs called follicles within the ovaries. Each follicle contains an immature egg and produces the hormone estrogen, preparing the uterine lining for potential pregnancy. Normally, one dominant follicle matures around the middle of the cycle and ruptures to release its egg, a process known as ovulation.
A follicular cyst develops when the dominant follicle fails to rupture and release the egg. Instead of collapsing, the follicle seals itself off, continues to grow, and accumulates follicular fluid inside. This continued growth results in a follicular cyst, typically larger than 2.5 centimeters in diameter.
The formation is often linked to a lack of the luteinizing hormone (LH) surge, the hormonal signal that normally triggers the follicle to break open. The granulosa cells lining the cyst may persist and continue to produce estrogen. This hormonal activity can sometimes lead to a decreased frequency of menstruation or abnormal bleeding patterns.
Recognizing Symptoms and Diagnosis
Most follicular cysts do not cause noticeable symptoms and are frequently discovered incidentally during routine pelvic examinations or imaging. When symptoms occur, they are typically mild, including a dull ache or pressure in the lower abdomen, often felt on the side of the affected ovary. Individuals may also report a feeling of fullness or bloating.
Less commonly, cysts can cause changes in the menstrual cycle length or result in abnormal uterine bleeding. If a cyst grows large or ruptures, it can lead to acute symptoms such as sudden, sharp pelvic pain, sometimes accompanied by nausea or vomiting. These intense symptoms require immediate medical attention to rule out complications like ovarian torsion.
Diagnosis relies primarily on imaging, specifically a pelvic ultrasound. Healthcare providers use transvaginal ultrasound to assess the cyst’s size, shape, and internal structure, confirming it is a simple, fluid-filled sac characteristic of a follicular cyst. A physical examination and review of the patient’s medical history and symptoms are also part of the diagnostic process. Blood work may be ordered to rule out other possible causes or evaluate hormonal status.
Treatment Options and Resolution
For most follicular cysts, the recommended approach is expectant management, or “watchful waiting,” because the majority resolve spontaneously. These cysts typically shrink and disappear on their own within one to three menstrual cycles (six to eight weeks). This resolution occurs as the body naturally reabsorbs the fluid.
During this period, providers usually schedule a follow-up ultrasound to confirm the cyst has resolved or is shrinking. Over-the-counter pain medications, such as acetaminophen or ibuprofen, can manage mild pelvic discomfort. Hormonal contraceptives may be prescribed to prevent the formation of new cysts in individuals who experience them frequently, but they do not shrink existing cysts faster.
Intervention is necessary only in rare instances, such as when a cyst is persistently large, causes severe symptoms, or appears abnormal on imaging. Acute, severe pain, especially if sudden and accompanied by fever or signs of shock, can indicate a ruptured cyst or ovarian torsion. Ovarian torsion is a medical emergency where the ovary twists on its supporting ligaments, cutting off its blood supply, requiring immediate surgical attention. Surgery to remove the cyst may also be considered if it does not resolve after several months.