Baby’s heart rate slowing??

Bri • Mom of 🩷🩵👼🏻🩷🤰🏼& due March 31, 2025!

I’m 21 weeks 4 days pregnant. Baby’s heart rate has always been in the 150’s to 160’s, but right after I hit the 20-week mark, I’ve noticed at home with my doppler that it’s now around 140-150. It’s causing me stress and anxiety that something’s wrong :-(. Anyone know anything about this? I will ask my doctor at my appt. next week!