At my 6 week ultrasound my baby's heartrate was at 75! They diagnosed it with bradycardia and told me that there was a 90% chance I would miscarry soon. 3 days ago I had my 20 week ultrasound and my little boy's heart rate was perfect at 135! He was just a late starter I guess. Subsequent ultrasounds showed normal heart rates(7 weeks- 115, 8 1/2 weeks- 176, 13 weeks - 148, 20 weeks- 135)