Ovarian cysts are very common and are frequently found in infertile women. However, there are of many types and cause considerable confusion - for both patients and doctors !
First, you need to understand that even a normal ovary will always have cysts ! The commonest type of ovarian cyst is just a normal ovarian follicle - the little fluid filled cavity in which the eggs grow. Usually, only one follicle develops per month. This follicular growth can be monitored by vaginal ultrasound. The follicle appears as a circular fluid-filled bubble on the screen, and can be seen when it is about 7 to 8 mm in size. It grows at about 1 to 2 mm per day, and is ready for ovulation when it measures 18 to 25 millimeters in diameter. Following ovulation, the follicle usually disappears from the scan picture completely and this is the best evidence of ovulation.
When a follicle gets to be bigger than about two centimeters or so, doctors call it a cyst. Please remember that it's often just a name game - a question of semantics. Thus, this kind of cyst is just an enlarged follicle ! Since it arises during normal ovarian function, it is called a "functional cyst" ( though the term dysfunctional might be better !) and nothing needs be done other than wait it out because it will usually dissolve on its own.
If the cyst is large, many doctors will use birth control pills to cause it to regress. Because pills suppress ovulation , they will usually suppress the cysts that develop as a result of this.
Can the cyst be more sinister ? Could it be an ovarian cancer, for example ? This can be a possibility, but the good news is that the chances are very low. For most women, the vast majority of cysts are benign. However, the fear of cancer causes some gynecologists to become trigger happy and perform a laparoscopy to find out what's going on and to remove it. Unfortunately, this unnecessary surgery often reduces the patient's fertility by reducing her ovarian reserve, since normal ovarian tissue is also sacrificed during the surgery.
When should you worry about the cyst being a serious problem ? Large cysts ( more than 5 cm in size) need to be monitored more carefully; especially if the ultrasound scan shows that there is solid tissue within the cyst ( the technical word for this kind of cyst is a complex cyst). Some doctors will use blood tests called tumour markers such as CA-125, to help find out the type of the cyst. These levels are increased in patients with some kinds of ovarian cancer, but unfortunately these tests are rarely helpful, because elevated levels can be found in a wide variety of other conditions as well.
For most simple ovarian cysts, watchful waiting is the best approach.
In the next post, I'll discuss some diseases which cause cysts, such as endometriosis and PCOD.