When is it to take the bad habit of sucking her thumb at what age? & what to prevent her from doing it ? She just turn 4 Months and started having that habit???
Usually when they start growing more teeth does it become a problem. It can often lead to an overbite. Right now it's just comfort to her and it's okay to let it go. You can try giving her different things to substitute (binkies, toys with chewy stubs, etc) if you're worried about it.
If it does become a habit and you can't get her to stop later on, there are non toxic nail polishes you can put on her thumb that have a bitter taste. It doesn't sound very nice, but it works 😂
@rhealize, thanks