Is it common to get a period so quickly when starting metformin?

Risks in starting a new birth control before you get your next period?

• I was on yaz birth control for about a year and my prescription ran out 2 weeks before my gyno apt. I wasnt on birth control for two weeks and she wrote me a new prescription for a different birth control. She said it would be best to just wait til i get my next period to start my new birth control. What would be the risk in starting the new birth control before i start my period

• Answer:

  The risk is that you might think you're protected when you're not. Birth control is designed to start at a certain time in your cycle, because of the hormone highs and lows that your body experiences. Wait until your next period before starting it. For the next couple of months, make sure your partners wear condoms.