For infertility patients, there are usually only a few cysts that need defining. First, as an egg develops over the course of a cycle, the egg surrounds itself with fluid i.e. a cyst. This is a follicle and is normal, and essential for reproduction. Sometimes one of these follicles fails to release to egg and remains throughout the next cycle. This can happen after a Clomid treatment or sometimes in women with irregular cycles. These are harmless unless they break and bleed, but usually by waiting a month or using birth control pills for a month, they will go away on their own. Occasionally, in IVF cycles the fluid can be removed vaginally by injecting a needle into the cyst and gently sucking out the fluid.
Another type of cyst seen somewhat infrequently for fertility patients is a cyst that forms when there is endometriosis in the ovary. These are called an endometrioma or a chocolate cyst. These have a very distinctive appearance on an ultrasound and usually can be identified by a simple pelvic ultrasound. Finally, some women have polycystic ovarian syndrome. Poly means many, so this is a situation where there are many cysts in the ovary. The ultrasound is used as one of the three criteria that are needed to make the diagnosis of PCOS. The cysts are small egg units (follicles) that have failed to grow and release the egg due to the increased levels of male hormone within the follicles. If there are 12 or more of these in one or both ovaries measuring 3-9 mm then that is termed a “polycystic ovary” by ultrasound.
A good takeaway from a ‘real’ physician (as opposed to Dr. Google) is that if a woman is told she has a cyst or many cysts, then the next logical step is to determine what type of cyst it is; a friendly normal egg unit or something more sinister?