ConditionWomen's & pregnancy health
Ovarian Cyst
An ovarian cyst is a fluid-filled sac on or in an ovary. Most are functional cysts that form as part of the normal menstrual cycle, cause no symptoms and disappear within 1 to 3 menstrual cycles. Others include endometriomas, dermoid cysts and cystadenomas, which may need treatment. Large cysts can cause pelvic pain, bloating or pressure. Sudden severe pain with nausea or fainting may mean a cyst has ruptured or twisted the ovary (torsion), which needs emergency care. Cancer is uncommon, especially before menopause.
Also called: Cyst on the ovary, functional ovarian cyst, follicular cyst, corpus luteum cyst, adnexal mass
At a glance
- What it is
- A fluid-filled sac in or on an ovary.
- Most common type
- Functional cysts (follicular or corpus luteum), which usually resolve in 1 to 3 cycles.
- Other types
- Endometrioma, dermoid cyst (teratoma), cystadenoma, hemorrhagic cyst; multiple small follicles in PCOS.
- Symptoms
- Often none; pelvic pain or pressure, bloating, pain with sex, irregular periods.
- Emergencies
- Rupture with internal bleeding, and ovarian torsion.
- Treatment
- Watchful waiting with repeat ultrasound; surgery for large, persistent, complex or suspicious cysts.
When to get help
Call 911 or go to the ER
- Sudden, severe pelvic or lower belly pain, especially on one side with nausea and vomiting (possible torsion)
- Pelvic pain with fainting, dizziness, a racing heart or shoulder-tip pain (possible internal bleeding)
- Pelvic pain with a positive pregnancy test or missed period (possible ectopic pregnancy)
- Pelvic pain with fever above 38 °C (100.4 °F) and vomiting
See a doctor within a day or two
- Increasing pelvic pain or pressure over a few days
- A known cyst with new, worsening pain
Book a routine appointment
- Persistent bloating, feeling full quickly, pelvic pain or urinary frequency for more than a few weeks, especially after age 50
- A cyst found on ultrasound that needs follow-up
- Irregular periods, acne and excess hair growth
- Painful periods and pain with sex
Usually safe to manage at home
- Mild one-sided pelvic twinges around mid-cycle that settle within a day (likely ovulation pain)
How ovarian cysts form
Each month, the ovary grows follicles, small fluid-filled sacs that each contain an egg. One follicle releases its egg at ovulation, then becomes the corpus luteum, which makes progesterone. Functional cysts form when this process goes slightly off course:
- follicular cyst: the follicle does not release its egg and keeps growing
- corpus luteum cyst: the corpus luteum fills with fluid or blood after ovulation
These are common and usually painless, and they disappear on their own.
Types of ovarian cysts
| Type | Description | Usually |
|---|---|---|
| Follicular cyst | Unruptured follicle | Resolves in 1 to 3 cycles |
| Corpus luteum cyst | After ovulation; may bleed (hemorrhagic cyst) | Resolves; can be painful |
| Endometrioma ("chocolate cyst") | Filled with old blood from endometriosis | Persists; may affect fertility |
| Dermoid cyst (mature teratoma) | Contains tissue such as hair, fat, teeth | Benign; removed if large or symptomatic; torsion risk |
| Cystadenoma | Benign growth from the ovary surface, can be large | Usually removed |
| Polycystic ovaries | Many small follicles, not true cysts | Part of PCOS |
| Cystic cancer | Rare before menopause | Needs specialist surgery |
Symptoms
Many cysts cause no symptoms and are found on an ultrasound done for another reason. When symptoms occur:
- dull or sharp pain on one side of the pelvis
- pelvic pressure, fullness or bloating
- pain during sex
- pain with bowel movements
- needing to urinate more often
- changes in periods
Complications
Rupture
A cyst can burst, often during exercise or sex. Most ruptures cause sudden, sharp pain that settles over a few days. A ruptured corpus luteum cyst can bleed significantly into the abdomen, causing dizziness, fainting and shoulder-tip pain, which is an emergency.
Ovarian torsion
A cyst, usually larger than about 5 cm, can make the ovary twist on its blood supply. Ovarian torsion causes sudden, severe one-sided pain, often with nausea and vomiting. It needs emergency surgery to save the ovary.
Risk factors
- reproductive age (functional cysts)
- fertility medicines that stimulate ovulation
- pregnancy (corpus luteum cysts)
- endometriosis
- previous ovarian cysts
- smoking
Hormonal birth control that stops ovulation reduces new functional cysts but does not shrink existing ones.
Diagnosis
- pelvic exam
- pregnancy test to rule out ectopic pregnancy
- transvaginal ultrasound: shows size and features. Simple, thin-walled, fluid-filled cysts are almost always benign. Complex features (solid parts, thick walls, blood flow) need further assessment.
- CA-125 blood test: mainly useful after menopause or with suspicious features; it is raised in many benign conditions
- MRI for unclear cysts
- risk scoring systems such as O-RADS help decide on follow-up or surgery
Treatment
Watchful waiting
Most simple cysts in premenopausal women need no treatment. A repeat ultrasound in 6 to 12 weeks confirms resolution. Small simple cysts after menopause are also common and often benign, and may be monitored.
Pain relief
NSAIDs such as ibuprofen or naproxen, following the label dose, and heat.
Surgery
Surgery, usually laparoscopic, is considered for cysts that:
- are large (often over 5 to 10 cm) or growing
- persist beyond 2 to 3 cycles
- cause significant symptoms
- have complex or suspicious features
- cause torsion or significant bleeding
Cystectomy removes the cyst and preserves the ovary; oophorectomy removes the ovary. Suspected cancer is managed by a gynecologic oncologist.
Frequently asked questions
What causes ovarian cysts?
Most ovarian cysts form during the normal menstrual cycle when a follicle does not release its egg or the corpus luteum fills with fluid. Other cysts are caused by endometriosis, benign growths such as dermoid cysts, and rarely cancer.
What does a ruptured ovarian cyst feel like?
A ruptured cyst usually causes sudden, sharp pain on one side of the lower belly, often during exercise or sex. Pain may spread across the abdomen. Dizziness, fainting or shoulder-tip pain suggest internal bleeding and need emergency care.
Do ovarian cysts go away on their own?
Most functional cysts disappear within 1 to 3 menstrual cycles without treatment. Endometriomas, dermoid cysts and cystadenomas do not usually go away and may need surgery if they are large or cause symptoms.
When should I worry about an ovarian cyst?
Seek emergency care for sudden severe pelvic pain, pain with fever or vomiting, or dizziness and fainting. See a doctor for persistent pain, bloating, feeling full quickly, or a cyst that is large, complex or found after menopause.
Can ovarian cysts affect fertility?
Most functional cysts do not affect fertility. Endometriomas and the endometriosis behind them can reduce fertility, and PCOS affects ovulation. Surgery on the ovary can sometimes reduce egg reserve, so it is planned carefully.
Sources
This guide was written from current patient and clinical guidance, including:
- American College of Obstetricians and Gynecologists: Practice Bulletin 174, Evaluation and Management of Adnexal Masses
- ACOG: Ovarian Cysts (FAQ)
- Society of Radiologists in Ultrasound: Management of Asymptomatic Ovarian and Other Adnexal Cysts, Consensus Conference Statement
- American College of Radiology: O-RADS US Risk Stratification and Management System
- MedlinePlus: Ovarian cysts
- NHS: Ovarian cyst