Not growing much for a few months? is this normal?

[OuiOui]

Have recently been joking how our 11mth old ds looks the same as he did when he was 6 months - this seemed kind of strange when our first dd was off the scale in weight.
He's ill at the moment so has been at the drs and she didn't say anything and anyway I wasn't worried until I looked at the growth chart.
Now, normally I never check these things and just go with the flow but I just had a look and am now a little concerned.
At 6.5 months he was 7 kgs , 70cm heightand now at 11 mths he's only 8.7 kgs and 72cm height - if the charts are to be believed then he was an average size 6.5 month but is now only average 9 month.
he's a good eater, a pretty good milk drinker (ave 5ooml/day) BUT not a great sleeper
Any explanations?
H

My ds is exactly the same. He was piling on the weight for the first few months and now doesn't seem to have grown or put on any weight for weeks and weeks! He's dropped down from the 75th to the 50th percentile in weight. However, my HV said it was quite normal around this age and is usually to do with the fact that they're moving around so much more - they're burning off those calories so much faster than they were before.

Try not to worry too much. I think we get so used to seeing those pounds and inches pile on at first that it's a bit of a shock when it all slows down. As long as he's generally happy, alert and eating well then there's almost certainly not a problem.