Its all up to chance...I was being monitored a few weeks ago for major pelvic pressure and in the course of a few hours the baby's heart rate went as high as 163 and as low as 120...it all depends in their activity and rest schedule hun. There's no proof it means a boy or a girl. Healthy heartbeat is all that matters :-)
My little girl's heart rate is in the 140s and I'm 26 weeks. She's been in the 140s since the beginning.
Sometimes those wivestales prove themselves
I'm 31 weeks and my baby girl heart rate has pretty much been in the ranges you stated above. I read that every babies heartbeat is different. I know the wives tale says higher heart rate is a girl lower is boy but there isn't a proven theory.
My girl was 155-158 whole pregnancy!
My sons started out high and now stays in the 140's