Siblings

4 year old must know his sister is coming soon because he is more attached to me than normal and acting like a 2 year old, sometimes younger. It's even occurring a bit with my 7 year old also but not as much. I DID go through this when I was pregnant with my 4 year old (7 year old regressed a few weeks before his brother was born) but this time seems to be worse. If you are having this problem what are you doing to stop it without giving in to the negative behavior. Anything would help. Thanks ladies.