a few things needed to be answered first
what is the baby's weight ?
does this distention come and go , or it is the same all the time ?
do you noticed any itching, discoloration of the skin or
skin rash on the legs ?
is she developmentally well ?
what is her nutritional status ?
a complete physical exam by the doctor will exclude
organomegaly ( big liver or big spleen) .
if the distention comes and goes , flat abdomen in the morning and big one in the evening this means that is some sort of maldigestion, most commonly from
carbohydrate at this age and some medicines are helpful with that
if this distention is present all the time I recommend the following tests : cbc ,
albumin level ,
thyroid function test , stool for reducing substsnces , celiac screen , abdominal songoraphy
I hope this helps