I'm having a girl and hers stay between 143 to 162. It doesn't really tell you the sex because my first daughter was higher and everyone assumed it was a boy. My pregnancies have been completely different even with the way I hold them so nothing is ever accurate.

You can't go by the heartbeat

My Son Stays Between 145-170 hard to say

My daughter has stayed between 140-168 up til now I'm 20 weeks.