If your baby is given bottles too early, before he learns to breastfeed well, he may be at risk for nipple confusion which may in turn put your milk supply at risk for never becoming fully established and result in your baby's frustration at and perhaps rejection of the breast.
During breastfeeding a baby's tongue, jaw, and mouth work together in a coordinated rhythm. This unique sucking action is one reason why breastfed babies overall have better oral development than bottlefed babies. Once the baby latches on, the tongue comes down and out as it cups the breast. The lips must be flanged out resembling a rose petal or a fish's lips. Letdown can sometimes takes several seconds to perhaps more than a minute to occur. The baby learns that he does not get an instant reward; he must "work" for mother's milk.
With bottlefeeding, the baby is instantly met with a flood of milk as a bottle will allow milk flow without active sucking. This sudden gush forces the baby to flip his tongue upward to help regulate the flow and prevent him from choking. His lips are pursed tightly around the firmer artificial nipple and no work is required of his jaws.
One study found that 95% of babies will become confused if given a bottle during the first 3-4 weeks of life. For some babies it may take many bottles before they show any nipple confusion; for others it can take only one or two. For this reason it is best to avoid offering your baby a bottle before he is 4 weeks of age.
What about pacifiers, you may ask. A pacifier must be considered an artificial nipple just as a bottle nipple is. When using a pacifier in the early weeks, watch your baby closely for signs of nipple confusion. If you notice any, it is best to limit or completely avoid pacifier use until the baby is older. Signs of nipple confusion in the baby include: pushing mother's nipple out of the mouth, crying in frustration at latch-on or shortly thereafter, pushing back from the breast, or trying to suck at the breast as he does with the bottle. Additionally, you may have sore nipples.
What if supplements are medically indicated before your baby is 4 weeks of age? There are a variety of feeding methods available that are satisfactory alternatives to bottle feeding. Even a very young baby can be fed with an eyedropper, feeding syringe, soft, flexible, medicine cup, spoon, bowl, or nursing supplementer which can be used at the breast or attached to a finger. If your doctor has advised supplements, please contact a lactation consultant or La Leche League leader in your area for additional support and encouragement. She will be able to assist you with alternative feeding methods and maintenance of your milk supply until baby is back on your breast completely.