Ovarian Cysts: Types, Symptoms & When to Worry

Ovarian cysts are sacs filled with fluid or semi-solid material that form on the surface of or within an ovary. They vary widely in size, from smaller than a pea to larger than a grapefruit, though most are small and cause no problems. Cysts can develop at any age, but they are most common during the reproductive years when the ovaries are actively producing eggs.

It is important to understand that developing a cyst on your ovary is often a sign that your ovaries are functioning normally. Each month during ovulation, a follicle (a small fluid-filled sac) develops on the ovary to nurture the maturing egg. This follicle is technically a type of cyst. In most cases, the follicle releases the egg and dissolves naturally. Problems arise only when cysts grow larger than expected, persist beyond a normal cycle, or develop characteristics that warrant further evaluation.

Ovarian cysts are broadly categorized as functional or non-functional. Functional cysts are the most common type and are related to the normal menstrual cycle. There are two subtypes: follicular cysts, which form when the follicle does not release the egg and continues to grow, and corpus luteum cysts, which form when the follicle releases the egg but the sac seals off and fills with fluid instead of dissolving. Both types are almost always benign and typically resolve within one to three menstrual cycles.

Non-functional cysts develop independently of the menstrual cycle and include several types. Dermoid cysts (mature cystic teratomas) are present from birth and can contain tissue such as hair, skin, or teeth — they sound alarming but are almost always benign. Endometriomas, sometimes called "chocolate cysts," develop when endometrial tissue (the lining of the uterus) grows on the ovary, often in association with endometriosis. Cystadenomas are cysts that develop from the outer surface of the ovary and can be filled with watery or mucous-like fluid; they can sometimes grow quite large. In rare cases, ovarian cysts may be cancerous (malignant), particularly in postmenopausal women.

Many ovarian cysts cause no symptoms at all and are discovered incidentally during a routine pelvic exam or an ultrasound performed for another reason. When symptoms do occur, they may include a dull or sharp ache on one side of the lower abdomen or pelvis, bloating or a feeling of heaviness in the abdomen, pain during sexual intercourse (especially with deep penetration), irregular menstrual periods or changes in menstrual flow, a frequent need to urinate (if the cyst is pressing on the bladder), and difficulty emptying the bowels.

The presence and severity of symptoms often depend on the size of the cyst, its location, and whether it is causing any complications. A small functional cyst may produce mild, brief discomfort around the time of ovulation, while a larger cyst can cause more persistent pain and pressure.

While most ovarian cysts are harmless, two complications require emergency medical attention: ovarian torsion and cyst rupture.

Ovarian torsion occurs when a cyst causes the ovary to twist on its blood supply, cutting off circulation. This is a surgical emergency. Symptoms include sudden, severe, one-sided pelvic pain that may be accompanied by nausea and vomiting. The pain is often described as sharp and unrelenting. Larger cysts (typically greater than 5 centimeters) carry a higher risk of torsion. If you experience sudden, severe pelvic pain, seek emergency care immediately — prompt surgical intervention is necessary to save the ovary.

Cyst rupture occurs when the wall of the cyst breaks open, releasing fluid into the pelvis. Small cyst ruptures may cause brief, sharp pain that resolves on its own. However, larger ruptures can cause significant pain, internal bleeding, dizziness, and in some cases, hemodynamic instability (a drop in blood pressure) that requires emergency treatment. If you experience sudden, intense pelvic pain, especially with lightheadedness or fainting, go to the emergency room.

The primary tool for diagnosing ovarian cysts is transvaginal ultrasound, which uses sound waves to create detailed images of the ovaries. Ultrasound can determine the size of the cyst, whether it is filled with fluid (simple cyst) or contains solid components (complex cyst), and whether there are features that raise concern for malignancy.

In certain situations, your doctor may order a CA-125 blood test. CA-125 is a protein that can be elevated in ovarian cancer, but it can also be elevated in many benign conditions, including endometriosis, fibroids, pelvic inflammatory disease, and even pregnancy. For this reason, CA-125 is most useful as a diagnostic tool in postmenopausal women, where an elevated level in combination with a concerning cyst on ultrasound may warrant further investigation. In premenopausal women, CA-125 results must be interpreted carefully in context.

Additional imaging such as MRI may be recommended if the ultrasound findings are inconclusive or if the cyst has complex features that need further characterization.

Treatment for ovarian cysts depends on the type, size, symptoms, and the patient's age and reproductive plans. For small, simple, functional cysts that are not causing significant symptoms, watchful waiting is the standard approach. Your doctor may recommend a follow-up ultrasound in six to eight weeks to confirm that the cyst has resolved.

Hormonal contraceptives, such as birth control pills, may be prescribed to prevent the formation of new functional cysts by suppressing ovulation. While hormonal contraceptives do not shrink existing cysts, they can reduce the likelihood of recurrence.

Surgical intervention may be recommended if a cyst is large (generally greater than 5 to 7 centimeters), persistent (not resolving after several menstrual cycles), causing significant symptoms, or has features on imaging that are concerning for malignancy. Cystectomy (removal of the cyst while preserving the ovary) is preferred when possible, especially in women who wish to preserve fertility. In some cases, oophorectomy (removal of the entire ovary) may be necessary. Minimally invasive laparoscopic surgery is the most common approach and typically allows for a faster recovery.

Most ovarian cysts do not affect fertility. Functional cysts are a normal part of the ovulatory process and do not impair your ability to conceive. However, certain types of cysts can have implications for fertility. Endometriomas are associated with endometriosis, which can affect fertility through inflammation, adhesions, and distortion of pelvic anatomy. Women with endometriomas who are planning pregnancy should work with their gynecologist or a reproductive endocrinologist to develop an appropriate treatment plan.

It is also common to discover ovarian cysts during pregnancy. Corpus luteum cysts, which support early pregnancy by producing progesterone, are frequently seen on first-trimester ultrasounds and almost always resolve on their own by the second trimester. Other types of cysts found during pregnancy are typically monitored with ultrasound, and surgery is reserved for cases involving torsion, rupture, or a high suspicion of malignancy.

If you have been diagnosed with an ovarian cyst and are concerned about its impact on your fertility, discuss your specific situation with your healthcare provider. In most cases, reassurance and monitoring are all that is needed.