The ovaries are part of the female reproductive system.
Women have two ovaries, with one located on each side of the uterus. These structures house the eggs that are released every month during the ovulatory cycle.
Ovarian cysts can form during a woman’s ovulatory cycle. Cysts are sacs that can contain fluid, air, or other tissue. They can form almost anywhere in the body and are often non-cancerous.
Ovarian cysts develop inside the ovaries and are often harmless and painless.
Cysts often naturally disappear within a few weeks to months. In fact, most women form at least one cyst per menstrual cycle. As women reach menopause, the likelihood of ovarian cysts reduces.
However, ovarian cysts can sometimes cause symptoms and pose a health risk if they rupture. In post-menopausal women, their presence increases the risk of ovarian cancer.
Ovarian Cysts vs. Polycystic Ovarian Syndrome
Having ovarian cysts is not the same as having polycystic ovarian syndrome (PCOS). The two conditions share similar symptoms, but PCOS is a condition relating to metabolism.
In PCOS, there are a large number of follicles on the ovaries that cause significant hormone imbalances, leading to irregular periods, excessive body hair, weight gain, difficulty becoming pregnant, and several other symptoms. Women with ovarian cysts do not often struggle with pregnancy in relation its presence.
Types of Ovarian Cysts
Functional cysts (common)
Follicular Cysts
In women with regular periods, the ovary releases a cell called a follicle every month. Inside the follicle is the egg, where it grows until it is mature. Normally, the follicle ruptures to release the mature egg. When the follicle fails to burst open, the egg continues to grow inside, and the follicle becomes a cyst. Follicular cysts can grow larger than 2.5 cm in diameter. Typically, follicular cysts do not cause symptoms and disappear in four to twelve weeks.
Corpus Luteal Cysts
When the follicle properly ruptures to release the egg, the empty follicle degrades into a mass of cells known as the corpus luteum. The corpus luteum is an important structure that releases the hormone progesterone, which prepares the next egg to be released during the next menstrual cycle.
In women who do not become pregnant from the released egg, the lifespan of the corpus luteum is 14 days before it dissolves. Corpus luteal cysts form when the corpus luteum does not dissolve. Instead, the rupture site reseals to form a cyst with fluid inside. These are larger than follicular cysts, reaching up to 10 cm in size, which can cause bleeding or pain in the ovary.
Non-functional cysts (uncommon)
Endometriomas: Endometriosis is a condition in which the inner lining of the uterus (the womb) grows outside of the uterus. Blood-filled cysts can form from this abnormal growth.
Dermoids: Cysts formed from fetal cells during birth.
Teratomas: Rare, cancerous cysts that presents as a tumor. They form from cells of the embryo.
Pathophysiology
Ovarian cysts form for several reasons. Hormonal problems and hormone-based drugs that promote ovulation increase the risk of forming cysts, especially functional ones. Pregnancy also naturally forms cysts that are beneficial for the embryo until the placenta grows. However, if these cysts do not disappear on their own and stay throughout the pregnancy, they can be harmful. Infections that travel to the ovary and fallopian tubes can also increase the risk of harmful cysts. Lastly, previous cysts can predispose women to having more.
Symptoms
Most ovarian cysts do not cause symptoms and disappear on their own.
However, large cysts may cause:
- Painful or aching bloating or swelling in the lower abdomen
- Sudden and sharp pain if the cyst ruptures
- Discomfort during intercourse, particularly with deep penetration
- Abnormal and heavy vaginal bleeding
- Pelvic and lower back pain
- Increased frequency of urination and defecation
If the cyst is large enough to cause twisting of the ovary, women may experience nausea and vomiting.
Diagnosis
Family physicians and specialists like obstetricians and gynecologists perform pelvic exams to feel for swelling and abnormalities on the ovaries. If there are signs of cysts, further examinations can be done to verify its presence.
Diagnostic Imaging: Ultrasounds are the most common method of diagnosing ovarian cysts. This technology uses sound waves to determine the shape, size, location, and mass of internal structures. Other tools such as magnetic resonance imaging (MRI) and computed tomography (CT) scans can be used as well.
Laparoscopy: A laparoscope is a thin instrument that can be inserted into your abdomen to visualize the ovary.
Pregnancy Tests: These are done to verify that cysts are not mistaken for a fetus.
Blood Samples: Your blood can indicate abnormal reproductive-hormone levels and the presence of cancer-related factors.
Treatment
Since cysts typically disappear on their own, doctors may recommend watchful waiting for several weeks before being re-examined. This is a common first-step if you do not display symptoms and the cyst is small. Routine ultrasounds are performed to keep track of its size until it disappears.
Other treatment options include medication and surgery.
Medication
There are no drugs that can shrink existing cysts but oral contraceptives (birth control pills) can stop or reduce ovulation. This will reduce the risk of recurring ovarian cysts.
Surgery
Laparoscopy can be used for both diagnosis and cyst removal. If the cyst is very large, a procedure called a laparotomy is performed under anesthesia. A laparotomy requires a large incision to be made in the abdomen. Cysts can be removed either without the ovary (ovarian cystectomy) or with the affected ovary (oophorectomy). However, if the cyst is found to be cancerous, a hysterectomy may be performed to remove both the uterus and ovaries to prevent cancerous tissue from spreading.
Prevention
It is not possible to prevent functional ovarian cysts from forming during normal ovulation. However, if you have recurrent cysts, doctors may recommend starting hormonal birth control with oral contraceptives to reduce or stop ovulation.
References:
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- Iglesia, C. B. (2018). Ovarian Cysts. Retrieved from https://www.womenshealth.gov/a-z-topics/ovarian-cysts.
- Grabosch, S. M. (2017). Ovarian Cysts. Retrieved from https://emedicine.medscape.com/article/255865-overview#a4.
- (2017). Ovarian Cysts. Retrieved from rhttps://www.acog.org/Patients/FAQs/Ovarian-Cysts#different.
- Higuera, V. (2017). Ovarian Cysts. Retrieved from https://www.healthline.com/health/ovarian-cysts#treatment.
- Healthwise Staff. (2016). Surgery for Ovarian Cysts. Retrieved from https://www.healthlinkbc.ca/health-topics/hw178611.
- (2017). What is the Difference between Ovarian Cysts and PCOS? Retrieved from https://www.londonwomenscentre.co.uk/info/news/difference-ovarian-cysts-pcos.