Ovarian Cysts
Ovarian cysts are sacs that develop on or inside an ovary. Most are fluid-filled and form as part of the normal menstrual cycle, often causing no symptoms and resolving on their own. Some cysts can contain solid tissue or other materials, and the type of cyst affects how it is managed. They may occasionally cause pelvic pain, bloating, or changes in menstrual cycles, and sometimes require monitoring or treatment.
Overview | Symptoms & Causes | Diagnosis | Treatment Options
What are Ovarian Cysts?
The ovaries are small, almond-shaped organs located on either side of the uterus. They produce eggs (ova) and hormones such as estrogen and progesterone, which regulate the menstrual cycle.
An ovarian cyst is a growth that develops on or within an ovary. Although the word cyst suggests a fluid-filled sac, ovarian cysts can be fluid-filled, solid, or a mixture of both, depending on the type. They are very common, especially during reproductive years, and most are harmless. There are several different types of ovarian cysts, including:
- Functional cysts: The most common type. These form as part of the normal menstrual cycle and are usually fluid-filled. They almost always resolve spontaneously within weeks.
- Dermoid cysts: Made up of various tissues such as hair, fat, or skin. They are often partly solid and are typically benign.
- Endometriomas: Caused by endometriosis, these cysts contain thick, blood-like material (“chocolate cysts”) and can have both fluid and solid components.
- Cystadenomas: Grow from the surface of the ovary and may be filled with thin, watery fluid or thicker mucus. They can become large but are usually benign.
- Cancerous (malignant) ovarian cysts: Much less common, especially in younger people. These may appear as complex cystic-and-solid masses. Most ovarian cysts are not cancerous, but certain features on scans or symptoms may prompt further investigation to rule out malignancy.
Understanding Ovarian Cysts
Many ovarian cysts cause no symptoms at all and are found by chance during a scan for another reason. When symptoms do occur, they can vary depending on the cyst’s size, type, and whether complications develop.
Common symptoms include:
- Pelvic or lower abdominal pain – this may be dull, aching, or sharp. Some people notice it more on one side.
- Bloating or a feeling of pressure or fullness in the lower abdomen.
- Changes in periods – such as irregular cycles, heavier bleeding, or spotting.
- Pain during intercourse (dyspareunia).
- Pain when opening bowels or pressure on the bladder, especially with larger cysts.
- Frequent urination if the cyst presses on the bladder.
Symptoms that suggest complications may include:
- Sudden, severe abdominal or pelvic pain – may indicate cyst rupture or ovarian torsion (twisting of the ovary).
- Nausea or vomiting, often occurring with torsion.
- Fever, if associated with infection or inflammation.
These severe or sudden symptoms require urgent medical attention.
Causes & Risk Factors
Ovarian cysts can form for several reasons, and in many cases they are a normal part of ovarian function. Most are benign (non-cancerous) and related to changes that occur during the menstrual cycle, but some have other underlying causes.
| Normal ovulation | The ovaries regularly produce small cysts as part of the menstrual cycle. These include follicular cysts (when the egg-containing follicle doesn’t release the egg) and corpus luteum cysts (after the egg is released). These are the most common type and typically resolve on their own. |
| Endometriosis | Endometriotic tissue on the ovary can form endometriomas (“chocolate cysts”), which may cause pelvic pain or period-related symptoms. |
| Benign growths | Cysts such as dermoid cysts (containing skin, hair, or fat) or cystadenomas (fluid- or mucous-filled growths) develop due to abnormal overgrowth of ovarian tissue. |
| Infection | Pelvic infections can occasionally lead to inflammatory or complex cystic structures around the ovaries. |
| Cancerous cysts (rare) | A small proportion of ovarian cysts may represent ovarian cancer. These are more common after menopause and usually have distinct features on scans that guide further investigation. |
Diagnosing Ovarian Cysts
If you have pelvic pain, bloating, irregular bleeding, or a lump is suspected during an examination, further assessment can help determine whether an ovarian cyst is present and what type it may be. Most cysts are benign, but understanding their features helps guide appropriate monitoring or treatment.
| Ultrasound | Ultrasound is the first-line and most important investigation for ovarian cysts. It can confirm whether a cyst is present and assess its size, shape, and internal contents - whether fluid-filled, solid, or mixed. The scan can also identify features that point toward specific types of cysts, such as endometriomas, dermoid cysts, or simple functional cysts, and highlight whether the appearance is reassuring or, rarely, concerning. Both transabdominal and transvaginal ultrasound may be used, with the transvaginal approach providing the clearest and most detailed view of the ovaries. |
| MRI Scan | If the ultrasound findings are unclear or the cyst has complex features, an MRI can provide additional detail. It offers a clearer characterisation of unusual or difficult-to-assess cysts and helps distinguish benign features from those that may need closer attention. |
Treatment Options
Management of ovarian cysts depends on the cyst type, size, appearance on imaging, and your symptoms. Many cysts require no treatment at all, while others may need monitoring or surgical removal.
| Monitoring | Many simple or functional cysts resolve on their own. If the cyst is small and has benign features, your clinician may recommend repeat ultrasound scans after several weeks or months to ensure it is shrinking or remaining stable. |
| Hormonal treatment | Hormonal contraception (such as the combined pill) may help prevent new functional cysts from forming. It does not treat existing cysts but can be useful for people who develop cysts frequently. |
| Treating underlying conditions | Some cysts form as part of other conditions, such as endometriosis. Managing the underlying condition can help reduce cyst formation and improve symptoms. |
| Surgical management | Surgery may be recommended if a cyst is large, persistent, causes significant symptoms, or has unclear or concerning features on imaging. Surgery may involve removing just the cyst (cystectomy) or, less commonly, removing the ovary if necessary. Most procedures are performed via laparoscopy (keyhole surgery). |
Your clinician will discuss the best course of management with you based on your individual circumstances, including the type of cyst, your symptoms, your medical history, and your personal preferences. Together, you can decide on the most appropriate and reassuring next steps, whether that involves monitoring, further tests, or treatment.
How can Lanthorn help?
Uterus & Ovaries Ultrasound - From £300
We provide high-resolution transabdominal and transvaginal ultrasound scans, which are the key first-line tests for assessing ovarian cysts. Ultrasound allows us to evaluate the cyst’s size and appearance, and to check for any reassuring or concerning features. It also helps guide whether monitoring or further assessment is needed.
Pelvic MRI Scan - £550
If additional detail is required - particularly for complex or unclear cysts - we can arrange a pelvic MRI. This offers a more detailed view of the pelvis and can help further characterise the cyst, providing clarity when ultrasound findings are inconclusive.
Referral to a specialist
If specialist input is needed, we can arrange a prompt referral to a trusted gynaecologist. This may be for further evaluation, ongoing monitoring, or procedures such as cyst removal, depending on what is most appropriate for you.
