1st check-up at 23 days old:

He gained half kilo making him 4 kilos. His body length is already 54 cm.

The little boy at 6 weeks old.

2nd check-up at 6 weeks old:

He weighs 5 kilos with length of 55 cm.
For sure he has gained more since then.   He is 7 weeks and 2 days old today.