My first ultrasound was 2/24/17 and I was around 9-10weeks and the baby's heartbeat was 163 bpm. At my second ultrasound 3/29/17 I was around 13 almost 14 weeks and baby's heartbeat was 168 bpm. Today 4/24/17 I am 17 weeks and 3 days, I only got to head the baby's heartbeat and it was 144 bpm. Is this normal? It went from 163 to 144. I've been stressing a lot does that have anything to do with my baby's heartbeat? Please ease my mind!