I've read a few posts from mommies who are concerned because their doctor can't find their baby's heart beat on a doppler. Well, I am 11wks, 3ds. At my checkup today my doctor really struggled to find it and it was slightly concerning. When she finally found it, baby kept moving and she had to chase it around. She continued to reassure me that baby is still small and moves around a lot....sometimes it's impossible to find it, but it doesn't typically alarm them. So...hopefully that helps ease some worry in anyone who hasn't been able to hear anything yet.