Nipple confusion occurs when young babies can't latch on properly, because they treated the nipple as a bottle. Nipple confusion is real, and it can happen to babies who were given a bottle or pacifier before they got the hang of nursing properly. The younger a baby, the more likely he or she is to suffer from nipple confusion.
Getting milk from a bottle is an awful lot easier than nursing, because the milk will come out all by itself, with no effort. Breastfed babies need to latch on the the nipple, hold the nipple in the correct place with their tongue, and make sucking motions to get the milk. Bottle-fed babies don't need to put the teat in very far, and make almost no effort to suck. It is no wonder that babies may encounter trouble when they try the preferred, no effort technique on the breast. Nipple confusion can be fixed (with persistence and sometimes the help of a lactation consultant), but it is better to prevent it. How?
The best way to prevent nipple confusion is to wait until your baby is at least four weeks old, and preferably until she is six weeks old. Once your baby has been breastfeeding for a while and her muscles are used to the process, it is not at all likely that he or she will unlearn it.