The two ovaries located in a woman’s uterus (one on each side) produce hormones like estrogen, and are essentially responsible for the menstrual cycle. Unfortunately, there are many types of ovarian cysts (sac-like cavities filled with fluids), that can mess up this cycle in every turn of the way.
Normally, a very small egg is released by the ovaries every month, an egg which then goes down the fallopian tube so that it becomes fertilized (or not, that is basically up to you), which in a word is what we call ovulation. During ovulation, the egg is covered (and protected) by a sac which dissolves when the ovaries release the egg. Sometimes, though, this sac is not dissolved and it swells up with fluids, thus creating a functional cyst (one of the most common types of ovarian cysts). Unless the cyst ruptures or bleeds out (in which case you will suffer an excruciating pain in the lower abdominal area), there is no need to be alarmed. Functional cysts are not dangerous, like other types of ovarian cysts which can be cancerous, and they usually dissolve on their own without taking any medication (so chances are you won’t even know you have one).
Polycystic ovary syndrome, on the other hand, can have many adverse effects and by no means should it be taken lightly. As the name implies, women with PCOS (polycystic ovary syndrome) suffer from multiple cysts in their ovaries. As a result, their menstrual cycle becomes irregular or it is completely absent, a condition also known as amenorrhea. Alternatively, ovaries may fail to release an egg, when they should, thus resulting in the condition called anovulation. Last but not least, polycystic ovaries can trigger the production of androgens (male hormones), which can in turn cause hirsutism (excessive body hair), it can obviously lower the chances of getting pregnant, and (even if a women does get pregnant) it is also associated with a high rate of miscarriages.
Other types of ovarian cysts include endometriomas, cystadenomas, and dermoid cysts. Endomitriosis is a condition that involves the development of uterine-lining tissue on the external side of the uterus, thus resulting in one of those types of ovarian cysts that can cause infertility and, of course, extreme pain. Cystadenomas are very similar to endomitriomas, but they differ in the kinds of fluids these cysts become filled with. As for dermoid cysts, those are filled with teeth, hair follicles, skin tissue, fat, blood, or sebum, and in general tissue from every part of the body.
Besides the aforementioned types of ovarian cysts, there are cysts that can be cancerous. Epithelial cell tumors, germ cell tumors, and stromal tumors are all such malignant types of ovarian cysts and they need to be removed as soon as possible. If you are experiencing pain in the abdominal area, irregular menstruation or any other suspicious symptoms, visit you gynecologist, let him run his diagnostic, and discuss with him the various treatments. Keep in mind that each type of cyst has its own treatment, and by no means should you rush into a treatment (for example taking birth control pills can work in some cases) just because a friend of yours happened to do so.