It's based off of your stating weight/height. For my first pregnancy I was told to aim for 30/35lb and this time around having leftover baby weight my dr lowered my goal to 25/30lb.
My sister is a taller than me and her aim was 45/50lb because.
Basically eat healthy and try and keeping you and baby healthy. If you gain lots of barely any pregnancy weight who cares
As for me,i think its 4 kilos