I hate to be negative, but it didn't work for me for my last pregnancy at all. I tried forever to hear the heartbeat with it, but could never get it. Also, mine said (inside the package) that you couldn't return it, b/c it was a "personal hygiene" item or something like that. I was a little annoyed to say the least.
I really hope yours works better than mine did. Maybe they have improved the technology since 2.5 years ago. Keeping my fingers crossed for you! Let us know if it does work, please?