its next to impossible to hear the babies heartbeat m8 – not TOTALLY impossible – but I wouldnt bother.
There are special fetal heartbeat stethoscopes that midwives used to use (look like a trumpet) but TBH its hard sometimes to hear the wee blighters even with a proper doppler ultrasound stethescope (what we use nowadays,)
If you want to really surprise her you should buy her a full on Ultrasound scanner like Tom cruise did for Katie 🙂
Having said that id send u one if I had a spare – but Ive only got my top quality littman – not for sale 🙂