This adorable top has been made by me using light weight Clover Green Wool/Lycra Interlock.  It is a soft and silky feeling wool.  Made from a size 6 month pattern.  If possible measure your baby to see if the fit is good.

Measurements for top - 

Armpit to end of sleeve - 7"

shoulder to bottom edge of waistband - 12"

chest - 21"

Wool needs to be gently hand washed and laid flat to dry.