Introduction

Ovarian cysts are fluid-filled sacs in the ovaries. Some have tissue inside them. The cysts are surrounded by a capsule and usually about the size of a cherry. Most ovarian cysts go away on their own.

These cysts often develop due to normal hormonal changes in puberty or during menopause. Sometimes ovarian cysts are already there at birth or are caused by something else, but that’s much less common.

It is estimated that about 10 out of 100 women have ovarian cysts. They are usually non-cancerous (benign) and rarely cause problems, so they generally don’t need to be treated. Surgery is only very rarely needed.

At a glance

• Ovarian cysts are small sacs that develop in the ovaries.
• Most of these cysts develop as a result of hormonal changes occurring during puberty or menopause.
• Ovarian cysts only rarely cause noticeable symptoms and generally don’t need to be treated.
• They sometimes affect the menstrual cycle, and very big cysts can be painful.
• Ovarian cysts can be removed in a procedure called laparoscopy.

Ovary with a cyst

Symptoms

Most women who have ovarian cysts don’t know that they have them. But some cysts cause dull pain in the lower abdomen (pelvic pain).

Ovarian cysts can also lead to problems with the menstrual cycle, such as heavy or irregular periods, or spotting (abnormal vaginal bleeding between periods). Menstrual cycle problems occur if the cyst produces sex hormones that cause the lining of the womb to grow more.

Very large cysts may push against the bowel or bladder. This can lead to a swollen tummy, a feeling of fullness and pressure, pain when urinating, or constipation.

If a cyst ruptures (bursts), it can be felt as a sudden pain – but usually doesn’t cause any other problems. The weight of the cyst can sometimes pull on the ovary and cause it to become twisted. This leads to sudden, severe, cramping pain on the affected side of the lower abdomen, as well as nausea, vomiting and a high pulse rate.

Causes

Most ovarian cysts develop during one part of the menstrual cycle (the growth and release of egg cells). Known as “functional cysts,” these mainly occur in puberty or during menopause. They may develop in one ovary or in both ovaries at the same time.

These are the most common types of functional ovarian cysts:

• Follicular cysts: Each egg cell is surrounded by a capsule known as a follicle. If the follicle doesn’t open and release the egg cell (if ovulation doesn’t occur), the follicle might gradually become filled with a fluid and turn into a cyst.
• Corpus luteum cysts: These occur when a corpus luteum fills with blood. The corpus luteum develops from the follicle that released the egg cell during ovulation. It secretes the sex hormones known as progesterone and estrogen.
• Theca lutein cysts: These mainly occur after infertility treatment with hormones. The hormones stimulate the growth of egg cells in the ovaries. Cysts may develop as a side effect.

There is also a special type of cyst known as chocolate cysts (endometriomas). These are filled with dark, thick blood. They can develop as a result of endometriosis, for example.

Dermoid cysts (which are not functional cysts) are less common. They may develop if a non-cancerous tumor grows and it contains things like skin cells and sebaceous glands. Sebaceous glands produce an oily substance (sebum) that usually keeps skin moisturized. Because the sebum in this kind of tumor can’t “escape,” it builds up inside the cyst. Dermoid cysts might be there at birth. They only rarely become cancerous (malignant).

In another illness known as polycystic ovary syndrome (PCO), there are a lot of small cysts in the ovaries. Women who have PCO produce too many male sex hormones (androgens), which prevent the egg cells from maturing properly.

Effects

Most ovarian cysts are 1 to 3 centimeters in size and go away on their own within a few months. They only rarely grow large enough to cause severe symptoms. In very rare cases they grow as big as 15 to 30 centimeters.

Complications are also rare. They may occur if the wall of the cyst ruptures (bursts) and the fluid leaks out into the space around it. Although ruptures can be painful, they are usually harmless. Only rarely do they lead to bleeding that needs to be stopped through surgery.

A more serious complication may occur if the ovary becomes twisted around the tissue that supports it. Known as ovarian torsion, this mainly happens in women who have larger cysts – often after jerky movements, for instance when playing tennis. Ovarian torsion is very painful. It may also cut off the blood supply to the ovary. If that happens, surgery is needed as soon as possible to prevent the ovary from dying.

Diagnosis

Ovarian cysts can be seen on an ultrasound. They are often discovered by chance, for instance when doing an ultrasound scan of the ovaries. Some cysts can be felt too.

If it is thought that you might have an ovarian cyst, the doctor will ask you about symptoms such as menstrual (period) problems and pain, and you may have a blood test.

Other examinations, such as a CT scan or laparoscopy (keyhole procedure to look inside your tummy), are only rarely needed. Diagnostic examinations are usually done to find out whether the changes in ovary tissue could be cancer. Although cysts are usually non-cancerous (benign), it’s not always easy to tell whether it’s a cyst or a tumor.

Treatment

If a cyst causes no symptoms, or only mild symptoms, it’s usually okay to wait and see what happens. Most cysts go away on their own. Depending on the results of diagnostic examinations, it’s sometimes a good idea to go for regular check-ups (every month or every few months) so the doctor can keep an eye on the cyst. If the cyst is painful, painkillers such as ibuprofen or other non-steroidal anti-inflammatory drugs (NSAIDs) can help.

If the cysts change over time or don’t get smaller and if the symptoms don’t go away, laparoscopy is an option. This procedure involves inserting thin instruments into the abdomen (tummy) through small cuts in the tummy wall. Doctors can then take a closer look at the cysts and remove them if necessary. But new cysts may develop after others have been removed.

In rare cases doctors suggest removing an ovary, or even both ovaries – for instance, if they think it could be cancer or that it will be difficult to cut the cysts out of the ovary tissue. Removing both ovaries can have a great impact on women’s lives, particularly younger women, because the operation immediately leads to menopause. The sudden drop in hormones can cause symptoms such as hot flashes, dizziness, headaches and nausea. And women can no longer become pregnant after menopause. Because of this, at least one ovary is kept, if possible – especially in women who wish to have (more) children.

Some doctors recommend treating ovarian cysts with the birth control pill. But the pill doesn’t help in the treatment of functional cysts. Although it reduces the amount of hormones produced in the ovaries and prevents ovulation, studies have shown that this doesn’t make the cysts go away any faster.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. In our topic "Health care in Germany" you can read about how to find the right doctor – and our list of questions can help you to prepare for your visit to the doctor.

Sources

• American College of Obstetricians, Gynecologists' Committee on Practice Bulletins - Gynecology. Practice Bulletin No. 174: Evaluation and Management of Adnexal Masses. Obstet Gynecol 2016; 128(5): e210-e226.
• Grimes DA, Jones LB, Lopez LM et al. Oral contraceptives for functional ovarian cysts. Cochrane Database Syst Rev 2014; (4): CD006134. [PMC free article: PMC10964840] [PubMed: 24782304]
• Royal College of Obstetricians & Gynaecologists (RCOG). The management of Ovarian Cysts in Postmenopausal Women. (Green-top Guideline No. 34). 2016.
• Weyerstahl T, Stauber M. Gynäkologie und Geburtshilfe. Thieme: Stuttgart 2013.
• Wolfman W, Thurston J, Yeung G et al. Guideline No. 404: Initial Investigation and Management of Benign Ovarian Masses. J Obstet Gynaecol Can 2020; 42(8): 1040-1050.e1041. [PubMed: 32736855]

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