Bottle types...?

Stacie

So my baby started off with tomme tippees as a newborn and would have 2-3oz every 2 hours. Doctor put her on Zantac for acid reflux and I switched her bottles to dr.brown she still drinks 3oz of milk every 2 hours and she’s 3 months already. She hardly finishes the milk. Tonight just now I gave her 4 ounces from tommee tippee bottles and she drank it a little faster and finished the whole thing. Maybe the flow of the nipples ? Now I’m worried I haven’t been feeding her enough formula and she’s just gets tired of sucking with the dr.brown nipples.