Dear Ritu;
It sounds like your OB/Gyn believes that you are not ovulating, and that perhaps you have a condition called Polycystic Ovarian Syndrome (PCOS). Metformin may help you ovulate, which would allow you to have normal periods, and have a chance of getting pregnant. This is a reasonable step to take.
Women who have PCOS tend to have long, irregular cycles, and often do not ovulate regularly. If your body produces estrogen, your uterus will fill up with blood, but without ovulation, you will produce no progesterone, and the inner lining of your uterus will not stabilize. This will result in you being unable to have a normal period.
I agree with the strategy of supplying progesterone (in the form of Prometrium) to you. This will mimic an ovulation, and hopefully allow your inner uterine lining (endometrium) to stabilize, and subsequently allow you to have a normal period. Unfortunately, I think the 200 mg dose of Prometrium is inadequate for this job. Perhaps trying 400 mg (2 of the 200 mg capsules nightly for 10 to 12 days) would be more successful; or even better, a series of three or four intramuscular injections of natural progesterone in oil (200 mg) each separated by a full day may be helpful. In any case, I agree with you that the birth control pill does not address the problem. It may (or may not) affect the bleedingóbut it will certainly bring you no closer to having a child.
Best,
John Gisla, MD