Ovarian Cyst Symptoms: Signs and What an Ultrasound Shows
Pelvic pain, persistent bloating or an unexpected cyst on a scan can be worrying. This guide explains the symptoms, cyst types and how pelvic ultrasound helps clarify what is happening.
If you have been living with a nagging ache on one side of your lower tummy, bloating that will not settle, or a scan report mentioning a cyst, it is understandable to want a clear answer.
An ovarian cyst can affect periods, sex, sleep and peace of mind. This guide explains the symptoms to notice, the main cyst types and what ultrasound can show.
Each month, the ovaries develop small sacs called follicles, each containing an egg. Usually, a follicle releases its egg and shrinks. Sometimes it does not, and continues filling with fluid. Once it is larger than about 3 cm, it is usually described as a cyst.
Ovarian Cyst Symptoms: What to Look Out For
Symptoms can range from a mild dragging sensation to pain that affects work, exercise or sex. They are more likely when a cyst grows, ruptures or twists, although many small cysts cause no symptoms.
- Pelvic or lower abdominal pain, often on one side.
- Pain during sex.
- Bloating or a swollen tummy.
- Needing to urinate more often.
- Difficulty emptying the bowels.
- Feeling full after eating only a small amount.
- Heavier, lighter or irregular periods.
These symptoms are worth investigating if they persist for more than a few weeks, regardless of the suspected cyst size.
What Does Ovarian Cyst Pain Feel Like?
Ovarian cyst pain often feels like a dull, heavy ache low on one side of the abdomen, on the same side as the cyst. It may come and go. Whether the pain is intermittent or recurring, it is reasonable to seek an explanation rather than simply tolerate it.
What Are the Types of Ovarian Cysts?
Most ovarian cysts are caused by hormonal changes during the normal menstrual cycle. These functional cysts are the most common type.
Functional cysts
Follicular cysts form when a follicle does not release an egg. Corpus luteum cysts form after ovulation when the remaining structure fills with fluid or blood. Most disappear within two or three cycles.
Dermoid cysts
These grow from cells capable of forming different tissue types and may contain fat, hair, skin or teeth. Although their description can sound alarming, they are usually benign.
Endometriomas
These cysts are associated with endometriosis and contain old blood. They can be linked with painful periods, pain during sex and fertility problems.
Cystadenomas
These develop from tissue covering the ovary and contain watery fluid or mucus. Most are benign.
What Size of Ovarian Cyst Is Dangerous?
Most small ovarian cysts are not dangerous. Clinicians consider the cyst’s internal appearance, your symptoms, age and menopausal status—not size alone.
For women who have not reached menopause, Royal College of Obstetricians and Gynaecologists guidance describes the following usual approach for simple cysts:
Swipe sideways to view the full table.
| Simple cyst size | What usually happens |
|---|---|
| Smaller than 5 cm | Usually no follow-up is needed. Most disappear within about three menstrual cycles. |
| 5–7 cm | An annual ultrasound may be recommended to monitor it. |
| Larger than 7 cm | MRI assessment or surgery may be considered. |
These thresholds apply to simple cysts before menopause. Complex cysts, significant symptoms, pregnancy or postmenopausal findings require individual clinical advice.
Can Ovarian Cysts Be Cancerous?
Most ovarian cysts are not cancerous. Before menopause, RCOG estimates that approximately 1 in 1,000 ovarian cysts causing symptoms is malignant, rising to around 3 in 1,000 by age 50.
Risk is higher after menopause. The NHS advises that postmenopausal cysts may be monitored with ultrasound and blood tests, even when they look simple, according to the individual clinical picture.
How Does Ultrasound Help Diagnose an Ovarian Cyst?
Ultrasound is usually the first imaging test. It shows where the cyst is, measures it and assesses whether it contains clear fluid, blood, solid tissue or internal divisions. This helps a specialist decide whether it is likely to resolve, needs monitoring or needs further assessment.
Two ways to scan the ovaries
- Transabdominal ultrasound: the probe moves over the lower abdomen. A comfortably full bladder is usually needed.
- Transvaginal ultrasound: a slim probe is gently inserted into the vagina. Because it sits closer to the ovaries, it provides clearer detail. It is optional and only performed with consent.
Blood tests and other scans
If a cyst looks complex, there is a relevant family history or the patient is postmenopausal, a doctor may recommend a CA 125 blood test. CA 125 can also rise with endometriosis, fibroids, infection or menstruation, so it must be interpreted alongside imaging. MRI is sometimes requested for further characterisation.
How Much Does an Ovarian Cyst Scan Cost in London?
Private ovarian ultrasound
The price includes a transabdominal scan and, with consent, a transvaginal scan; assessment of both ovaries and any cyst or mass; findings explained on the day; and a written report within 24 hours.
Book an Ovarian UltrasoundWhat Does Treatment for an Ovarian Cyst Look Like?
Treatment depends on cyst size and appearance, symptoms and menopausal status. Many small, simple functional cysts disappear within a few months and require no treatment.
- Monitoring: a repeat ultrasound after several weeks or months may show whether the cyst has reduced or disappeared.
- Pain relief: a GP can recommend suitable pain relief and reassess symptoms affecting daily life.
- Surgery: removal may be recommended when a cyst is large, persistent, growing, painful or unusual. Many cysts can be removed with keyhole surgery while preserving healthy ovarian tissue.
- Combined contraceptive pill: it does not make an existing functional cyst resolve faster. It may reduce formation of new functional cysts by preventing ovulation.
Book an Ovarian Ultrasound in London
A pelvic scan can feel daunting when you are already worried. Our experienced team explains the findings on the day and provides a written report within 24 hours.
Experienced specialists
Scans are performed and reported by registered Ultrasound Consultants in a CQC-registered clinic.
Your comfort comes first
A female sonographer is available on request at no extra cost. Transvaginal scanning is optional and requires consent.
Answers before you leave
Findings are explained during the visit, followed by a written report within 24 hours.
Appointments seven days
Clinics are open 9am–7pm, and no GP referral is needed.
Visit us at 27 Welbeck Street, near Bond Street, or 54–56 Victoria Street, St Albans.
Get a clear answer about your symptoms
Book a £219 ovarian ultrasound for a detailed assessment of both ovaries, an explanation on the day and a written report.
References
Frequently Asked Questions
Do I need a GP referral for an ovarian cyst scan?
Does a transvaginal scan hurt?
Do ovarian cysts go away on their own?
What is the 1-2-3 rule for ovarian cysts?
Medical disclaimer: This article provides general information and does not replace personalised medical advice. Seek urgent assessment for sudden severe pelvic pain, faintness, vomiting, fever or heavy bleeding.
Written and medically reviewed by Mr Pedram Aghaei, Co-founder and Medical Writer, London Private Ultrasound. Reviewed against NHS, RCOG and professional ultrasound guidance. Last reviewed 19 October 2026; next review due 19 April 2027.