I have cysts on my ovaries that become larger than normal when I am off birth control. I tried to go off it once and conceived, and my cysts became huge. I miscarried, and the doctor put me back on birth control to reduce the cysts. I would like to go off the pills again but fear the return of the cysts. We are interested in having a family and would not like the cysts to cause any problems. Any suggestions you have would be greatly appreciated.

H.K.

Not all cysts are abnormal. Each time you ovulate, a follicle develops on your ovary. This structure, which holds the maturing egg, is actually a fluid-filled cyst that reaches about an inch in size by the time the egg is released. It's quite common for the follicle to continue to enlarge after egg release (ovulation). If the cyst gets as large as two inches or so, or if the same cyst persists from month to month, that may be a sign that you have a persistent ovulation-related cyst. These are called functional cysts, because they result from normal processes of your ovary. Such a mass may also be a small tumor. Rarely are these tumors malignant (cancerous), but if they become too large or do not go away on their own, surgery may be necessary.

As you've already learned, the first step in treating persistent cysts is often to see if a month of two of birth control pills will make the cysts go away. If the problem continues to recur, regular use of birth control pills to prevent new functional cysts from forming can reduce the frequency of the problem.

Some functional cysts, called anovulatory follicular cysts, may occur if you do not ovulate regularly. Monitoring and charting your basal body temperature (BBT) when you are off the pills can provide clues as to whether you are ovulating. If not, your physician will recommend the appropriate tests to determine the reason, and may then either treat any conditions that are diagnosed or else suggest therapy with the fertility drug clomiphene to restore normal ovulatory cycles. Closely monitored clomiphene treatment may help you conceive and even reduce your risk of developing large ovarian cysts.

Another form of functional cyst, called a hemorrhagic (meaning "blood-filled") cyst, may be the first clue that you have an underlying blood-clotting disorder. Blood-clotting tests for PT, PTT and bleeding time can rule out this sort of problem. Certain types of medication may also increase your chances of developing hemorrhagic cysts.

Assuming you are ovulating and do conceive, you do not need to worry that the presence of cysts will interfere with a pregnancy. The existence of such cysts will not make miscarriage more likely. However, elevations of hCG, a hormone produced during pregnancy, can directly stimulate growth of a functional cyst -- which is probably why your cysts became huge after you conceived.