Feeding a baby from the breast and feeding him from a bottle require completely different mouth and tongue motions. Breastfed babies must use different feeding and swallowing skills than bottle-fed babies, and they learn these skills through their experiences during the first weeks of breastfeeding.
For example, breastfed babies must take all of the nipple and as much of the areola as possible into their mouth compressing the breast between the tongue below and the roof of the mouth above. By comparison, bottle-fed babies typically use the lips to grip the tip of the bottle nipple (or a pacifier).
“Nipple confusion” is the term used to describe what happens when breastfed babies are given artificial nipples before their breastfeeding skills are fully developed.
These babies often try to apply the (less complex) movements of bottle-feeding while breastfeeding. Consequently, some of these babies experience confusion and have more difficulty breastfeeding. Most babies can learn to switch between the two feeding methods, but this takes time. While there is no rigorous scientific evidence to support nipple confusion, it is best to avoid introducing bottle nipples and pacifiers until both you and your baby have learned to breastfeed well, after about the first 4–6 weeks.
If a bottle is introduced too early, some babies may choose to ignore their mother’s breast altogether, since milk flows from bottles more easily. If you need to interrupt breastfeeding for any reason, especially during the first 4–6 weeks, you can avoid nipple confusion by using a teaspoon, eye dropper, or cup to feed your baby your expressed milk.