I am battling PCOS, so what has happened to me may not happen to everyone. I was sleeved December 5, 2011 and thus far I have had 6 periods. In the four months prior to surgery I didn't have one at all. Surgery was a Monday, by that Friday I had one. And just about every other week since then. I didn't do any birth control the first few weeks per doctors orders, but then I started back on Trinessa. That didn't help at all, and my insurance changed and finally I could afford to use NuvaRing again, my favorite birth control out of all I've been on! I'm hoping that NuvaRing will do the trick. My surgeon said usually if cycles get messed up they start to fix themselves around the 3 month mark.
Good luck!