head circumference

J
Has anyone's babies head dropped in growth percentile? My daughter was born in 92nd and now at 6mo she's close to 25th. Weight and length have been around 70-80. I'm starting to get really concerned, at 4mo she was at 44Th and ped said she wasn't worried and felt it was more due to head shape. However from our measurement it's barely grown in 2 mo. Her appointment isn't until 20th. 
The back of her head is a little flat but I don't know if that would effect it that much.
Thoughts?