Blood pressure spiking then dropping?

Mia • M O M M Y 💕

So I need to know the science behind this. Before I got pregnant I had normal blood pressure no issues at all. Now when I get it done they ALWAYS have to check it twice. It’ll be ridiculously high and I’ll tell them to do it again then it’ll be normal. I’m not crossing my legs, my arm is laying flat im not talking. I’m doing everything both times that I should but it always does this now! Like it’ll happen on the blood pressure machines it’ll happen if they do it manually it’ll go from 150/80 to 130/40 within 30 seconds. It’s so weird that my body is doing that. 🤷🏼‍♀️