this is my 5th pregnancy, and I've never experienced this before. hoping someone has and can explain…

this is my 5th pregnancy, and I've never experienced this before. hoping someone has and can explain it to me. i am 16 weeks, for the last month I'd say when I stand for a few minutes my legs and feet get tingles and they start to get itchy. I don't know what this is from or why it is happening