you are less likely to miscarry when you have hit 3 months. Even with a heartbeat you can still have a miscarriage, don't consider it something that you can change if its meant to happen then it will with or without your help. I heard my babies heart beat and a week later he or she was already gone. Don't worry to much about it though, just be happy. Enjoy it if you are worried then call your dr, they should be able to walk you through any question or concerns that you may have. Hope you have a bouncing happy baby.