Ovarian Cysts: Which Are Normal and Which Need Checking
Most ovarian cysts are a normal part of the menstrual cycle and fade on their own. Here is how to tell the common, harmless kind from the ones that need a scan, a follow-up or urgent care.
TL;DR: Ovarian cysts are very common, and most are functional cysts that form as part of your cycle and disappear within a few months. Other types, like dermoids, endometriomas and cystadenomas, may need monitoring or surgery. Sudden severe pelvic pain, especially with vomiting, fever or feeling faint, needs urgent care. Any cyst found after menopause should be followed up.
Hearing the word "cyst" after a scan can make your stomach drop. Maybe you went in for pelvic pain, or a fertility check, or a scan for something else entirely, and the sonographer mentioned a cyst on your ovary. Suddenly you are searching late at night and reading the worst. Here is the calmer picture: ovarian cysts are extremely common, most cause no symptoms at all, and the majority go away without anyone doing anything. Knowing which kind you have, and which signs mean you should act quickly, takes a lot of the fear out of it.
What is an ovarian cyst?
An ovarian cyst is a fluid-filled sac that develops on or in an ovary. The NHS describes them as very common and says most occur naturally and go away in a few months without treatment. The RCOG adds that almost all cysts found before the menopause are benign, meaning not cancer, and that many women never know they had one.
Cysts can be thin-walled and filled only with fluid, called simple cysts, or more complex, containing thicker fluid, blood or solid areas. That difference matters, because it shapes what your doctor suggests next.
The normal kind: functional cysts
Every month, an egg grows inside a small fluid-filled pocket in your ovary called a follicle. Usually the follicle bursts, releases the egg, and shrinks back down. Sometimes that does not go to plan, and this is where functional cysts come from. They are the most common type by far.
- Follicular cysts form when a follicle does not release its egg, or does not empty and shrink afterwards, so it keeps filling with fluid (NHS).
- Corpus luteum cysts form after the egg has been released. The leftover structure, which makes progesterone, can fill with fluid or a small amount of blood (MedlinePlus).
Functional cysts are linked to your cycle, so they only happen before menopause. According to ACOG, they often go away without treatment within 6 to 8 weeks. If a small simple cyst turns up on a scan and you feel fine, the usual plan is to leave it alone or rescan later to check it has gone.
One useful detail: the combined pill will not shrink a cyst you already have, though it may stop new ones forming (RCOG).
The other types worth knowing
Less common cysts come from abnormal cell growth rather than your monthly cycle. The NHS calls these pathological cysts. Most are still benign, but they are more likely to grow, cause symptoms or need surgery.
- Dermoid cysts (also called teratomas) develop from the cells that make eggs, and can contain tissue like hair and fat. They are usually benign and can grow during the reproductive years (ACOG).
- Endometriomas form when endometriosis, tissue similar to the womb lining growing outside the womb, affects the ovary. They are filled with old blood, which is why you may hear them called "chocolate cysts". If you have painful periods, pain during sex or trouble conceiving, read our guide to endometriosis.
- Cystadenomas grow from cells on the outer surface of the ovary. They are usually benign but can become very large (ACOG).
What symptoms can a cyst cause?
Most cysts cause no symptoms and are found by chance on a scan. When they do cause symptoms, it is usually because they are large, bleeding, bursting or twisting. According to the NHS and RCOG, you might notice:
- pelvic pain, from a dull heavy ache to a sharp pain, often on one side
- pain during sex
- a bloated or swollen tummy
- feeling full quickly after eating a little
- needing to wee more often or more urgently
- difficulty emptying your bowels
- changes to your periods
These symptoms overlap with lots of other conditions, from fibroids to infections to bowel problems, which is exactly why they deserve a proper look rather than a guess. Our guide to pelvic pain causes walks through the wider list.
When is an ovarian cyst an emergency?
Get urgent help if you have sudden, severe pelvic or abdominal pain, especially with vomiting, fever, dizziness, faintness or weakness. These can be signs that a cyst has burst and is bleeding, or that the ovary has twisted on its blood supply (ovarian torsion), which needs treatment quickly to save the ovary (womenshealth.gov, NHS).
In the UK, call 999 or go to A&E if the pain is severe, or call NHS 111 if you are unsure. In Lagos, Nairobi, Accra or Johannesburg, go straight to the nearest hospital emergency department rather than waiting it out with painkillers at home. If there is any chance you could be pregnant, say so, because sudden one-sided pain can also be an ectopic pregnancy.
Do cysts after menopause need checking?
Yes. After menopause you no longer ovulate, so functional cysts should not form, and the NHS notes a slightly higher chance that a cyst could be cancerous. That does not mean most are. Many postmenopausal cysts are simple and harmless. But the usual approach is closer monitoring: the NHS says regular ultrasound scans and blood tests over about a year are usually recommended, and the RCOG guideline recommends a CA125 blood test alongside the scan.
Separately, if you have bloating, feeling full quickly, losing your appetite or losing weight without trying on most days for two weeks or more, see a doctor whatever your age (MedlinePlus). These can be early signs of ovarian cancer and are easy to brush off. If you are navigating midlife changes more broadly, our piece on menopause for African women may help.
Are PCOS "cysts" the same as ovarian cysts?
No. The small "cysts" seen in PCOS are egg follicles that have stopped developing before ovulation because of altered hormone levels (NHS). They are small, usually numerous, and harmless in themselves. This is part of why the condition was renamed polyendocrine metabolic ovarian syndrome, or PMOS, in 2026: it is a hormonal and metabolic condition, not a disease of cysts. You can have PCOS with no visible follicles on a scan, and you can have a functional cyst without having PCOS. Our guide to PCOS symptoms, causes and treatment explains the full picture.
How are cysts treated?
Treatment depends on the cyst's size and appearance, your symptoms and whether you have been through menopause. The RCOG says a simple cyst under 5 cm that causes no pain usually needs no treatment, a simple cyst of 5 to 7 cm should get a follow-up scan, and larger or complex cysts may need an MRI or surgery. When surgery is needed, it is usually keyhole (laparoscopic) surgery, and surgeons aim to remove only the cyst and keep the ovary, especially if you want children in future.
If you are given a "watch and wait" plan, ask when your next scan should be, and what symptoms should bring you back sooner. Writing those answers down helps. So does knowing what to ask before you go in, which we cover in how to talk to your gynaecologist.
Keeping track between scans
A cyst plan often means weeks of waiting, and it helps to notice what your body is doing in that time. With Asele, you can log pelvic pain, bloating and period changes alongside your cycle, so you can see whether pain clusters around ovulation or your period. You can ask Amara questions in Yoruba, Hausa, Igbo, Swahili, French or English. And the Health Brief turns your logs into a pre-visit summary you can take to your doctor, so your follow-up starts with facts rather than fuzzy memories. Find us at Asele.
This post is education, not medical advice. If you have been told you have a cyst, follow the plan your clinician gives you, and never sit on sudden severe pain.
References
- NHS. Ovarian cyst. nhs.uk
- NHS. Ovarian cyst: causes. nhs.uk
- American College of Obstetricians and Gynecologists. Ovarian Cysts. acog.org
- Royal College of Obstetricians and Gynaecologists. Ovarian cysts before the menopause. rcog.org.uk
- Royal College of Obstetricians and Gynaecologists. The Management of Ovarian Cysts in Postmenopausal Women (Green-top Guideline No. 34). rcog.org.uk
- MedlinePlus, US National Library of Medicine. Ovarian cysts. medlineplus.gov
- US Office on Women's Health. Ovarian cysts. womenshealth.gov
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