What does this body language mean?

I have studied body language extensively for business but have never run across an answer about this action. When I begin to interact with a female in any context and let’s say they have a low cut top on, and as they begin to talk they adjust it up to make sure things are covered more. Do they feel uncomfortable around me? Most of the time I’m not thinking twice about it and than they do that adjustment thing like I’m looking. Don’t get it????