The ovaries (OH-vuh-reez) are a pair of organs in the female reproductive system. They are located in the pelvis, one on each side of the uterus. The uterus (YOO-tur-uhss) is the hollow, pear-shaped organ where a baby grows. Each ovary is about the size and shape of an almond. The ovaries produce eggs and female hormones. Hormones are chemicals that control the way certain cells or organs function.
Every month, during a woman's menstrual (MEN-stroo-uhl) cycle, an egg grows inside an ovary. It grows in a tiny sac called a follicle (FAH-lih-cull). When an egg matures, the sac breaks open to release the egg. The egg travels through the fallopian (fuh-LOH-pee-ihn) tube to the uterus for fertilization. Then the sac dissolves. The empty sac becomes corpus luteum (LOO-tee-uhm). Corpus luteum makes hormones that help prepare for the next egg.
The ovaries are the main source of the female hormones estrogen (ESS-truh-juhn) and progesterone (proh-JESS-tuh-rohn). These hormones affect:
the way breasts and body hair grow

A cyst is a fluid-filled sac. They can form anywhere in the body. Ovarian cysts (sists) form in or on the ovaries. The most common type of ovarian cyst is a functional cyst.
Functional cysts often form during the menstrual cycle. The two types are:
Other types of ovarian cysts are:
Many ovarian cysts don't cause symptoms. Others can cause:
If you have these symptoms, get help right away:
Doctors most often find ovarian cysts during routine pelvic exams. The doctor may feel the swelling of a cyst on the ovary. Once a cyst is found, tests are done to help plan treatment. Tests include:
Watchful waiting. If you have a cyst, you may be told to wait and have a second exam in 1 to 3 months. Your doctor will check to see if the cyst has changed in size. This is a common treatment option for women who:
It may be an option for postmenopausal women.
Surgery. Your doctor may want to remove the cyst if you are postmenopausal, or if it:
The two main surgeries are:
Birth control pills. If you keep forming functional cysts, your doctor may prescribe birth control pills to stop you from ovulating. If you don’t ovulate, you are less likely to form new cysts. You can also use Depo-Provera®. It is a hormone that is injected into muscle. It prevents ovulation for 3 months at a time.
No, ovarian cysts cannot be prevented. The good news is that most cysts:
Talk to your doctor or nurse if you notice:
Most functional ovarian cysts occur during childbearing years. And most of those cysts are not cancerous. Women who are past menopause (ages 50–70) with ovarian cysts have a higher risk of ovarian cancer. At any age, if you think you have a cyst, see your doctor for a pelvic exam.
*cited from: womenshealth.gov