My daughter has always been around 140. I think the whole heart rate thing is a myth.
With my daughter she was always around 160. I'm pregnant with a boy and his heart rate is always around 150. I never really thought of heart rate girl or boy since it isn't very accurate
My first daughter her heat rate was 150s and my second child was in the 140s and she's a girl so I feel it's all up in the air for the heart rate being a boy or girl thing...