I take Metformin 1000mg 2 times a day. I asked my current doctor if I could go off them because I haven't noticed any types of changes in my body (still overweight and can grow a beard in a matter of days if not taken care of). He told me that Metformin basically kept ovaries from creating cysts on them. I was diagnosed at age 16 and have never had cysts that I know of. I had an ultrasound done at that time but not since then. I know that I have no problems with ovulation or with having normal periods since 2002. Prior to that I had periods only about 3 times a year. I don't know the true reason my periods are so normal now, but I know that about that time I began a low-carb diet (only went on it for about 6 months). When researching the low-carb lifestyle I learned that low-carb can help a woman become more regular with her periods...seemed to have worked for me.