The first time I took it for 3 months, but not the 3 times a day. More like 1-2 a day and bam, I was pregnant with miracle baby #1. I had no real faith in it working. I'd been TTC for 6 years, seen 3 other doctors, 2 that were specialists and happened to pick a new OB to have a physical done so I could adopt. She mentioned PCOS (the first I'd heard of it) and refused to put me on the pill (I was giving up) and said to try it. If anything, I would lose some weight. I called 3 months later to ask to be put on the pill and she wanted to see me in person to see how the metformin was working. 2 weeks later my pregnancy test was positive. So were the other 5 tests that I took that week in disbelief. :)
It took me almost a year of trying for miracle baby #2 with metformin. I was also going through a very stressful time in my life and didn't think it would happen again. It did. :) Best of luck to you!!! Many do not understand the struggles to conceive those precious babies.