7w Today! Ultrasound good and bmp 131 - boy or girl?!?

Abby

I am pregnant with my second and so curious if my two-year-old daughter will have a baby brother or sister. Her heart rate was 153 beats per minute at seven weeks, and today the heart rate was 131 so it makes me think it’s a boy. Anyone have any theories on this?!? Lol, just trying to pass the time until I have bloodwork done to tell me. 💕💙💕💙💕💙💕