- Apr 25, 2013
Yes I know it's via an ultrasound. I never said anything about how the heart rate is detected. Using a stethoscope is only viable after 18-20 weeks.It's not arbitrary, that's when the fetus has an actual heart. You can only hear a heartbeat without the use of an ultrasound at around 20 weeks
The heart hasn't formed yet at 6 weeks. What you're hearing at that point is not a beating heart and the "beat" isn't actually audible without an ultrasound. If you used a stethoscope you would not hear anything. What you are picking up at 6 weeks is an electrically-induced flutter of a part of the fetal tissue that might eventually become a heart as the embryo develops. That's far from a sure thing at 6 weeks.
Also the fetal heart is fully formed by the 10th week so the first trimester is meaningless here.
Point remains it is detectable and separate from the mother even when it is still a flutter.