Can dogs sense pregnancy?

I am taking a test tomorrow, as AF should come if I am not pregnant. I am curious though if any of the woman on here have had there dogs start acting differently due to pregnancy. My sweet baby Molly is not usually cuddley but all of a sudden she is very cuddley and wants to lay her head against my stomach. My husband and I have been trying for a few months and we've had Molly for over a year and usually we have to force her to cuddle with us. I've been a little naseuos but that's the only symptom.

UPDATE. Molly knew something was going on before we did!!