Newborn lip quivers?

Question

why does my 18 day old baby's bottom lip quiver when she eats? it only happens sometimes.

Answer 1

A newborns lip will quiver from time to time due to an immature nervous system.  

Answer 2

I asked the same thing

it stimulates letdown so the baby will get better breastmilk flow (and yes babys that are fed formula will do it too)

Answer 3

Their muscles aren't strong enough yet so the lip quivers. Its nothing to worry about.