How long should you let your baby sleep in her sleep positioner ??

My baby is 4 months old and she will only sleep in the positoner.

I was told by my mother (a pediatrician) to take it o ut of my sons crib once he was able to roll over and move around in the crib. Apparently children have been known to lay on them in such a way face down that they can suffocate as they are a foam material and not very breathable.
I have heard until they begin to roll over. I took my son out of it at around 2-3 months because when I would wake up in the morning he had wiggled down in between the two side pieces and I was scared he might not be able to breathe if he fell asleep against it. It took him awhile to get used to not having it...it helped elevating his matress because we had the positioner that had an inclined pad. Afterawhile he was okay and got back to sleeping through the night. Just do what you think is best....if you think it might propose a problem or it worries you that she still has it then take it out. If not leave it in until she begins to roll or wiggles out of it.
If positioner helping the air way, just leave it there and watch over from time to time.

Baby Parenting Guide