HR on doppler


Always loud and clear but past two times it's hard to find at first lots of swooshing and when I do sounds a tad muffled and not as strong ( heart rate always stay 136-143) but these past two times not clear and pronounced ? I have an anterior placenta been moving from time to time but I don't know what's normal or adequate for movement 🤷🏼‍♀️ first time mom and I'm lost lol