my baby is not drinking bottle or breast milk

my daughter is 3 weeks old and since the day i started her to feed the milk my daughter is not drinking milk neither breast milk nor bottle milk when i took her to the docter he told me that is fine give her liquid milk so i started liquid milk. No matter what kind of milk i try like bottle or breast milk she's having trouble to drink milk. i do lot search in the internet by now my daughter should be at least 8 lbs by she's not even reach seven pounds. what should i do? is she has some kind of a sucking problem or something else? i'm very concern about her.

[Renee Radenberg]

Have you tried to change to a few different types of nipples on the bottle? She needs to be on baby formula not regular milk at this age because regular milk does not have the nutrients an infant needs to grow. If she still not able to suck with the different nipples, then have your MD get her evaluated for sucking skills. Infant sucking mechanisms do not start until about 30 weeks in the womb and sometimes later.

[adriano]

I agree that you need to take her tp the doctor. Sucking skills may be affected which is not good since its important for infanrts...maybe it could be the nipple of the bottle...