Gynaecology · Women's Health
Are ovarian cysts dangerous? A specialist's guide
Ovarian cysts are one of the most common findings in women's health — and one of the most worried-about. If a scan has mentioned a cyst or you've been searching your symptoms, here's what actually matters and when a cyst is (and isn't) a cause for concern.
What is an ovarian cyst?
A cyst is a fluid-filled sac. Ovarian cysts are extremely common and in most cases, are a normal part of how the ovaries work. Many form and disappear on their own across a menstrual cycle without ever causing symptoms. The important question is rarely “is there a cyst?” but rather “what type of cyst is it and is it behaving in a way that needs attention?”
Functional cysts vs other types
Broadly, ovarian cysts fall into two groups — and the difference matters far more than the fact a cyst is present.
Functional cysts
- Linked to normal ovulation
- Usually harmless
- Often resolve on their own over a few weeks to a couple of cycles
- Example: a corpus luteum cyst
Other (non-functional) cysts
- Don't come and go with the cycle
- Include dermoid cysts, endometriomas and cystadenomas
- More likely to need review or treatment
- Assessed on their individual features
Are ovarian cysts dangerous?
For most women, usually not. The great majority of ovarian cysts are benign and a large proportion of simple cysts resolve without any treatment. Assessment isn't about alarm — it's about identifying the small number of cysts that behave differently, so they can be managed early.
Two situations warrant prompt attention: a cyst that causes sudden, severe pain (which can signal a complication such as twisting or rupture) and a cyst with features on imaging that need further characterisation. Both are manageable and both are reasons to be assessed rather than reasons to panic.
“The question is rarely ‘is there a cyst?’ — it's what type and how it's behaving.”
Symptoms and red flags
Many cysts cause no symptoms and are found incidentally on a scan done for another reason. When symptoms do occur, they can include pelvic pain or pressure, bloating or changes in your cycle.
Seek urgent medical care if you have:
- Sudden, severe one-sided pelvic or abdominal pain
- Pain with nausea or vomiting
- Pain with fever, dizziness or feeling faint
Sudden severe pain with vomiting can be a sign of ovarian torsion (a twisted ovary), which is a surgical emergency. Prompt assessment protects the ovary.
When does an ovarian cyst need treatment?
It depends on more than size. Whether a cyst needs more than monitoring comes down to its appearance on ultrasound, whether it persists over time, your symptoms and your stage of life — not any single measurement.
This is why searching “is a 7cm cyst dangerous?” rarely gives a useful answer: a large, simple, functional cyst can be far less concerning than a smaller cyst with complex features. Most simple cysts are simply monitored, because so many resolve on their own. The full picture is what guides the decision.
How are ovarian cysts assessed?
The mainstay of assessment is a pelvic ultrasound, which is accurate, safe and widely available. Specialists use validated ultrasound criteria (such as the internationally used IOTA rules) to characterise a cyst's features and estimate the likelihood that it is benign. In selected cases a blood test (such as CA 125) or an MRI may add information. Together these help distinguish the reassuring majority from the minority that need closer follow-up or surgery — and where surgery is appropriate, keyhole (laparoscopic) surgery is generally preferred.
Frequently asked questions
Are ovarian cysts normal?
Yes — functional ovarian cysts are a normal part of the menstrual cycle and are very common in women of reproductive age. Most cause no problems and resolve on their own.
Is a 7cm ovarian cyst dangerous?
Size alone does not determine risk. A large simple cyst may be low-risk, while a smaller complex cyst may warrant closer review. What matters is the cyst's appearance on ultrasound, whether it persists and your symptoms — which is why a proper assessment is important.
What is a corpus luteum cyst?
It is a normal functional cyst that forms after ovulation each month. It will resolve and is harmless.
Can the emergency contraceptive pill cause ovarian cysts?
Hormonal changes can influence ovulation and cyst formation. Functional cysts are common regardless. Any cyst that persists or causes symptoms should be assessed on its own merits rather than assumed to be caused by one factor.
Can an ovarian cyst affect fertility?
Most functional cysts do not affect fertility. Some types, such as endometriomas, can be relevant to fertility and are worth discussing individually with a specialist.
Ovarian cyst assessment on Sydney's North Shore
Dr David Krones is a specialist obstetrician and gynaecologist who assesses and manages ovarian cysts for women across Sydney's North Shore. He consults at North Shore Private Hospital in St Leonards and operates at North Shore Private and The Mater Hospital in Crows Nest, conveniently located near St Leonards, Crows Nest, North Sydney, Lane Cove, Chatswood and the surrounding North Shore and Northern Beaches Suburbs. Assessment usually begins with a pelvic ultrasound alongside a review of your history and symptoms, so a clear plan can be made for your individual situation.
Phone: 02 9053 1245
If you've been told you have an ovarian cyst or you're experiencing pelvic pain, speak with your GP about a referral to see Dr Krones in St Leonards.
Request an appointmentA GP referral is required for specialist consultations.
References
- Cathcart AM, et al. Adnexal masses during pregnancy: diagnosis, treatment, and prognosis. Am J Obstet Gynecol. 2023. doi:10.1016/j.ajog.2022.11.1291
- Nezhat FR, et al. Pathophysiology and Clinical Implications of Ovarian Endometriomas. Obstet Gynecol. 2024. doi:10.1097/AOG.0000000000005587
- Shetty J, et al. IOTA Simple Ultrasound Rules for Triage of Adnexal Mass. J Obstet Gynaecol India. 2019. doi:10.1007/s13224-019-01229-z
- Vilendecic Z, et al. Accuracy of IOTA Simple Rules, ADNEX Model, RMI, and Subjective Assessment for Preoperative Adnexal Mass Evaluation. Gynecol Obstet Invest. 2023. doi:10.1159/000529355
- Scheier E. Diagnosis and Management of Ovarian Torsion: Current Insights. Open Access Emerg Med. 2022. doi:10.2147/OAEM.S342725
This article is for general education and does not replace individual medical advice. Please consult your GP or specialist about your own circumstances.