This varies from woman to woman, but in general, the heart beat should be visible on an ultrasound by the sixth week of pregnancy. It’ll look something like a little flicker in your baby’s chest, if the ultrasound actually picks it up. But if you’ve reached your sixth week and you still haven’t seen the heartbeat, don’t worry just yet. Sometimes doctors miscalculate just how far along you are, and you may have to wait another three to five days to see anything. You’ll be surprised what a difference just a few days can make!