I purchased this for my 4 month old's baptism.  I ordered a 12 month bc he is 18 pounds and long for his age plus the reviews stated that it runs small.  It was barely long enough (he is 27 inches).  The worst part was that the buttons do not stay fastened.  They would pop open every time he moved. Plus, there is not one right in the middle so his diaper was sticking out the whole time. It was a beautiful knit jumpsuit and would have been perfect had it been made a little better.