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Your guide to understanding ovarian cysts

We share expert information about ovarian cysts, including common symptoms to look out for, diagnostic testing and available treatment options.

An ovarian cyst is a small, fluid-filled sac that develops in an ovary or on its surface. Ovarian cysts are very common and girls and women of any age can get them. In most cases they are harmless and go away without needing any treatment. However, sometimes an ovarian cyst can cause problems. We take a look at the types of ovarian cysts, their causes, symptoms and treatments.

The ovaries are two small organs, about the size and shape of an almond. There is one on either side of the womb (uterus), and they form part of the female reproductive system. The ovaries have two main functions:

  • One ovary releases an egg around every 28 days as part of the menstrual cycle
  • The ovaries also produce and release the sex hormones oestrogen and progesterone. These hormones play a vital role in reproduction

Sometimes, a small, fluid-filled sac will develop on one of the ovaries. This is called a cyst. In most cases, a cyst is painless and causes little or no symptoms. Over the course of a lifetime, many women will develop a cyst.

Cysts occur as part of the normal process of the ovaries. They are mostly harmless and generally disappear after a few months without treatment. Occasionally, a cyst can rupture, causing severe pain.

Ovarian cysts can affect just one ovary or sometimes they can affect both at the same time.

Ovarian cysts can be split into two broad types. These are:

  • Functional ovarian cysts: These are the most common type of cyst. They develop as part of the menstrual cycle, and are usually harmless and shot-lived. Typically, a functional ovarian cyst will disappear on its own within two or three menstrual cycles.
  • Pathological ovarian cysts: These are much less common and are the result of abnormal cell growth.

Ovarian cysts can also be caused by an underlying condition, such as endometriosis. This occurs when cells that normally grow inside the womb develop on the outside and attach to the ovaries, resulting in a cyst.

Most ovarian cysts are non-cancerous (benign). However, a small number are cancerous (malignant). Cancerous cysts are more common if you have been through the menopause.

A small number of women may develop a condition called polycystic ovary syndrome. This occurs when the ovaries contain a large number of small cysts, which causes the ovaries to enlarge. If left untreated, polycystic ovaries can cause infertility.

Ovarian cysts often develop naturally as part of the menstrual cycle. They can also affect women who have been through the menopause. The ovaries normally grow cyst-like structures, called follicles, each month. These release an egg when you ovulate. Functional ovarian cysts are linked to the menstrual cycle and can be split into two groups:
  • Follicular cyst: During the menstrual cycle, an egg grows in a sac, called a follicle, which is located inside the ovaries. This follicle contains fluid that protects the egg as it grows. This follicle then breaks open and releases an egg, which travels down the fallopian tubes where it can be fertilised by sperm. Normally, after releasing an egg, the follicle shrinks and disappears. However, sometimes it does not release an egg or does not discharge its fluid. When this happens, the follicle can swell and become a cyst.
  • Corpus luteum cyst:Normally, a follicle disappears once it has released an egg. However, occasionally the opening can become blocked, which results in the build-up of fluid inside the follicle. This results in the formation of a corpus luteum cyst.

Functional cysts are non-cancerous (benign) and are usually harmless. Occasionally, they can cause symptoms, such as pelvic pain. However, most disappear in a few months without needing any treatment.

Pathological cysts are caused by abnormal cell growth. They are not related to the menstrual cycle and can develop before and after the menopause.

Pathological cysts develop from either cells that have been used to create eggs or cells that cover the outer part of the ovary. Occasionally, these cysts can burst or grow large enough to block the blood supply to the ovaries.

Typically, pathological cysts are non-cancerous, however, a small number are cancerous.

In some cases, ovarian cysts are caused by an underlying condition, such as endometriosis. This occurs when the tissue that normally lines the womb starts to form outside it, such as in the fallopian tubes, ovaries, bladder, bowel, vagina or rectum. Ovarian cysts do not normally indicate an increased risk of ovarian cancer.

In most cases, an ovarian cyst will not produce any symptoms and will go away within a two or three months. An ovarian cyst will only cause symptoms if it ruptures, becomes very large or blocks the blood supply to the ovaries. When any of these occur, you may experience:

A ruptured ovarian cyst usually occurs when it has become so big that it starts to press on nearby nerves or organs due to its size. If an ovarian cyst bursts, you are likely to feel intense pain and experience internal bleeding.

If your doctor thinks that you may have an ovarian cyst, they may refer you for an ultrasound scan. 

The cyst will then be monitored by with a repeat scan every few weeks. The doctor may also refer you to a gynaecologist.

Blood tests may also be taken if your doctor is concerned that the cyst might be cancerous. The tests look for high levels of chemicals that indicate ovarian cancer. However, high levels of these chemicals may also indicate another cause of the cyst, such as:

In most cases, ovarian cysts will disappear in a few months without the need for treatment.

If you do need treatment then this will depend on several factors, such as the size and appearance of the cyst or whether you have had the menopause.

In most cases, the doctor will take a watchful waiting course of action. This means that you will not have any immediate treatment, other than an ultrasound a few weeks later to check whether the cyst has gone.

Your doctor may recommend you to have regular ultrasound scans and blood tests if you have been through the menopause. If the scans show that the cyst is still there then surgery will be an option to remove it. Surgery may also be recommended if there is a possibility that the cyst could be cancerous.

There are two types of surgical procedures that can be performed to remove ovarian cysts. These are:

Laparoscopy: This is a type of keyhole surgery, where small cuts are made in your abdomen. A small tube-shaped microscope with a light on the end is then inserted through the incision. The cyst is then removed. The wound is closed using dissolvable stitches.

Laparotomy: This procedure is used for larger cysts or for cysts that may be cancerous, and it involves making a larger incision into the abdomen. The cyst and ovary may be removed for further testing. The wound is closed using staples or stitches.

Both procedures are performed under a general anaesthetic.

If the test results show that the cyst is cancerous then you will have further treatments, such as surgery to remove the ovaries and surrounding tissue.

The treatments for cysts caused by endometriosis or polycystic ovary syndrome may include painkillers, hormone medication or surgery.

Ovarian cysts do not normally affect your fertility or your ability to become pregnant. Endometriosis and polycystic ovarian syndrome may, in some situations, affect your ability to become pregnant.

In most situations, surgery to treat a cyst does not affect your ability to become pregnant if both ovaries remain intact.

If one of your ovaries needs to be removed, the remaining ovary will still release hormones and eggs as usual. This means that your fertility should not be affected, although you may find it harder to become pregnant.

In rare cases, such as if the cyst is cancerous and both ovaries need to be removed, the surgery will trigger an early menopause. This means you will no longer produce any eggs. Make sure you discuss your fertility concerns with your surgeon before your operation.

A consultation with an experienced gynaecologist is often the quickest and simplest way to resolve your problem.

They will be able to diagnose the cause of your pain and talk with you about the best treatment options for your specific situation.

An appointment with an experienced Consultant at your nearest BMI hospital can be helpful. They will assess and diagnose the cause of your symptoms and then discuss any suitable treatment options for your specific situation. To schedule your visit, book a specialist appointment online today.

To find out more about the 10 most common gynaecological conditions in the UK, download our series of Women's Health Matters 2021 reports.

These reports are based on the survey responses of more than 10,000+ women currently battling a gynaecological condition. We share intricate healthcare journeys, coping methods and candid, first-hand portrayals of what living with a women’s health issue is really like. We also cover:

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