First, Congrats on your new grandbaby!!! :o)  Does she have CAH?  Is she a salt-waster?  Or are you just worried this might be a sign of CAH?  My daughter Loghyn (16 mths SWCAH) was a little chunky then . . . but she was on some pretty high steroids until then too . . . how much did your grand-daughter weigh at birth?  Loghyn was 8 lbs 13.5 ozs at birth.  She went into crisis at 3 days old.  Went into the NICU on high stress doses of steroids.  And came home 2 days later at a little under 11 lbs!! 

Jess