Do dogs know you're pregnant?

Branae • Mommy of 3 sweet boys and baby #4 on the way❤️
This past week my male dag has been SUPER attached to me. He is usually attached to my husbands side, but this past week he only wants to be with me and he is always laying right on top of me or he has his head on my stomach.. AF is due on Saturday.. I'm TTC.. Ive heard that dogs become more attached when you are pregnant. Does anyone know? Thanks!