Spotting early pregnancy

Adrianna

So I'm 7 weeks 3 days pregnant for 3 to 4 days have had brown spotting and is now starting to clear up I have had two ultrasound done Wensday and Thursday heart beat was 130 just curious if anyone else had this happen. As well it's my third pregnancy but I just worry I let my obgyn know but I'm not sure what's causing the spotting