hey guys, with regards to doppler, nothing is proven about it causing any effects, it is a controversial topic in sonography circles. I personally think it is ok to use it to listen after 12 weeks as the heart is mostly developed after this period. And when your doctor uses it, it is usually after 12 weeks and only for a short period of time and gives you peace of mind that bub is ok which is a good thing. Us sonographers that don't use it before 12 weeks know about the data out there and choose just to be safe, just in case! I personally wouldn't get a home doppler to listen to bubs heartbeat, but it is a personal choice. As BMJ said, millions of babies have had ultrasounds and don't have heart damage. IN my opinion ultrasound saves lives through detection of things such as ectopic pregnancies and placenta praevias, which women wouldn't have survived 100 years ago, yet the apparent 'negative' effects it may have has never been proven. As long as it is being used by people who have trained and learnt all of the physics behind it then I believe it is justified. I agree with thermolicious that if you want to hear bubs heart then get a stethoscope! Old fashioned but works!