Ovarian Cysts
A dull ache on one side, bloating, or a cyst spotted on a scan? Most ovarian cysts are harmless fluid-filled sacs that form as a normal part of your cycle and clear up on their own.
General education, not a diagnosis. SHELY is pre-launch — “Talk to someone” adds you to our experts waitlist; we don’t offer bookings yet.
An ovarian cyst is a fluid-filled sac that forms on or inside an ovary. They are very common and, most of the time, completely harmless — many form and disappear as a natural part of the menstrual cycle without ever being noticed.
The most common kinds are functional cysts, which are linked to ovulation. Each month a follicle releases an egg; if that follicle doesn't open or seals back up, it can fill with fluid and become a cyst. These usually resolve by themselves over a few menstrual cycles.
Less commonly, cysts form for other reasons — such as endometriosis or growths that aren't related to the cycle. The vast majority are benign, but because some need monitoring, a doctor may suggest a repeat ultrasound to check that a cyst is shrinking rather than growing.
Signs & symptoms
- A dull ache or heaviness on one side of the lower belly
- Bloating or a swollen feeling in the abdomen
- Pain during sex, often felt deep on one side
- Pelvic pain around the middle of your cycle (ovulation)
- Feeling full quickly or needing to pee more often
- Irregular periods or changes in your usual cycle
- Most cysts cause no symptoms at all and are found by chance on a scan
Types
Follicular cyst
Forms when the follicle holding an egg doesn't open to release it and instead fills with fluid. Usually harmless and clears within a few cycles.
Corpus luteum cyst
Forms after the egg is released if the empty follicle seals up and fills with fluid. Common and usually resolves on its own, though it can occasionally bleed.
Endometrioma ('chocolate cyst')
A cyst filled with old blood, caused by endometriosis growing on the ovary. More likely to cause pain and may need treatment.
Dermoid cyst
A benign growth present from birth that can contain tissue like hair or skin. Usually harmless but may be removed if it grows large or twists.
What causes it
- Normal ovulation, which produces most functional cysts
- Hormonal cycles where a follicle fails to release its egg or reseals
- Endometriosis, which can form blood-filled cysts on the ovary
- PCOS, where many small follicles collect on the ovaries
- Pregnancy, which can sustain a cyst formed early on
- Pelvic infections that spread to the ovaries
When to seek help
Most cysts need only watchful waiting, but see a doctor for persistent pelvic ache, bloating that doesn't settle, or pain during sex. Seek emergency care immediately for sudden, severe pelvic pain — especially with fever, vomiting, dizziness, or feeling faint — as this can mean a cyst has twisted (ovarian torsion) or ruptured and needs urgent attention.
How SHELY helps
SHELY Care
Track where and when pelvic pain strikes across your cycle, so patterns linked to ovulation become clear to you and your doctor.
Symptom Checker
Describe one-sided pain or bloating to understand whether it sounds routine or worth getting scanned.
SHELY Varsity
Plain-language guides on what an ultrasound finding really means and when a cyst genuinely needs treatment.
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Pick a topic to explore what we know about Ovarian Cysts. Educational only — not a diagnosis.
- A dull ache or heaviness on one side of the lower belly
- Bloating or a swollen feeling in the abdomen
- Pain during sex, often felt deep on one side
- Pelvic pain around the middle of your cycle (ovulation)
- Feeling full quickly or needing to pee more often
- Irregular periods or changes in your usual cycle
- Most cysts cause no symptoms at all and are found by chance on a scan
- Normal ovulation, which produces most functional cysts
- Hormonal cycles where a follicle fails to release its egg or reseals
- Endometriosis, which can form blood-filled cysts on the ovary
- PCOS, where many small follicles collect on the ovaries
- Pregnancy, which can sustain a cyst formed early on
- Pelvic infections that spread to the ovaries
Follicular cyst
Forms when the follicle holding an egg doesn't open to release it and instead fills with fluid. Usually harmless and clears within a few cycles.
Corpus luteum cyst
Forms after the egg is released if the empty follicle seals up and fills with fluid. Common and usually resolves on its own, though it can occasionally bleed.
Endometrioma ('chocolate cyst')
A cyst filled with old blood, caused by endometriosis growing on the ovary. More likely to cause pain and may need treatment.
Dermoid cyst
A benign growth present from birth that can contain tissue like hair or skin. Usually harmless but may be removed if it grows large or twists.
Most cysts need only watchful waiting, but see a doctor for persistent pelvic ache, bloating that doesn't settle, or pain during sex. Seek emergency care immediately for sudden, severe pelvic pain — especially with fever, vomiting, dizziness, or feeling faint — as this can mean a cyst has twisted (ovarian torsion) or ruptured and needs urgent attention.
SHELY Care
Track where and when pelvic pain strikes across your cycle, so patterns linked to ovulation become clear to you and your doctor.
Symptom Checker
Describe one-sided pain or bloating to understand whether it sounds routine or worth getting scanned.
SHELY Varsity
Plain-language guides on what an ultrasound finding really means and when a cyst genuinely needs treatment.
Symptoms
- A dull ache or heaviness on one side of the lower belly
- Bloating or a swollen feeling in the abdomen
- Pain during sex, often felt deep on one side
- Pelvic pain around the middle of your cycle (ovulation)
- Feeling full quickly or needing to pee more often
- Irregular periods or changes in your usual cycle
- Most cysts cause no symptoms at all and are found by chance on a scan
Causes
- Normal ovulation, which produces most functional cysts
- Hormonal cycles where a follicle fails to release its egg or reseals
- Endometriosis, which can form blood-filled cysts on the ovary
- PCOS, where many small follicles collect on the ovaries
- Pregnancy, which can sustain a cyst formed early on
- Pelvic infections that spread to the ovaries
Types
Follicular cyst
Forms when the follicle holding an egg doesn't open to release it and instead fills with fluid. Usually harmless and clears within a few cycles.
Corpus luteum cyst
Forms after the egg is released if the empty follicle seals up and fills with fluid. Common and usually resolves on its own, though it can occasionally bleed.
Endometrioma ('chocolate cyst')
A cyst filled with old blood, caused by endometriosis growing on the ovary. More likely to cause pain and may need treatment.
Dermoid cyst
A benign growth present from birth that can contain tissue like hair or skin. Usually harmless but may be removed if it grows large or twists.
When to seek care
Most cysts need only watchful waiting, but see a doctor for persistent pelvic ache, bloating that doesn't settle, or pain during sex. Seek emergency care immediately for sudden, severe pelvic pain — especially with fever, vomiting, dizziness, or feeling faint — as this can mean a cyst has twisted (ovarian torsion) or ruptured and needs urgent attention.
How SHELY helps
SHELY Care
Track where and when pelvic pain strikes across your cycle, so patterns linked to ovulation become clear to you and your doctor.
Symptom Checker
Describe one-sided pain or bloating to understand whether it sounds routine or worth getting scanned.
SHELY Varsity
Plain-language guides on what an ultrasound finding really means and when a cyst genuinely needs treatment.
Frequently asked
Are ovarian cysts dangerous?
Most are not. The majority are small, functional cysts that come and go with your cycle and never cause harm. A doctor watches a cyst over time mainly to confirm it is shrinking, not to treat it.
Do ovarian cysts mean I have cancer?
Almost never. The overwhelming majority of cysts are benign. Doctors assess features on ultrasound and, if needed, a blood test to decide whether any follow-up is required, but a routine cyst is not a sign of cancer.
Can ovarian cysts affect my fertility?
Common functional cysts don't affect fertility. Cysts linked to endometriosis or PCOS can play a role, which is why the underlying condition — rather than the cyst itself — is usually what's treated.
How do I know if a cyst has burst?
A ruptured cyst often causes sudden, sharp pain on one side, sometimes with light spotting. Many settle on their own, but severe pain with dizziness, fever, or vomiting needs urgent medical care.
✔ Written from established medical guidance — independent clinical review in progress
This guide is for general education and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your health. In an emergency or crisis, see our crisis support resources.