My paed gave me a "calculation" he uses on newborns:

Birthweight will drop, and should go back up to birthweight, in the first 5 days post birth
Then ABOUT 150g a week
By 6 weeks old, ABOUT 1kg above birthweight

That said, he was also clear to say to me that the above is just a guide, and that all babies are different, and that we should gauge the demeanor & appearance of our babies as well as the scales.

How do you feel Aiden is fairing? Scales aside, is he content? Lots of wet nappies?

It looks like he is perfectly on track.......bare in mind that the 150-200g a week is an average........he may only put on 100g one week, then stack on 250g another week?

Hope that puts your mind at rest a little?