How beautiful to have heard the heartbeat!!

Shyly, I've been feeling the same way you have d/t my previous losses.
Do you ladies know what week you are "guaranteed" to hear a heartbeat? Is a fetoscope as sensitive as a doppler? I'm going on 10 weeks now, but I don't want my m/w to even try until it's definitely possible to hear it. The first time I was pregnant, we couldn't get a heartbeat -- which led to the u/s that brought us terrible news. So, I still have some PTSD surrounding fetoscopes. So, anyone know what week is good to listen with a fetoscope?
Thanks! And Congrats again!!
