Use of pacifier in the early weeks can also cause problems. If you want your baby to take a pacifier, I would introduce it by the time he is one month old, but preferably not during the first two weeks of nursing. Some babies refuse to ever take a pacifier. Some become addicted to them and are still carrying them to Kindergarten. I think that the babies who become attached to pacifiers would have become thumb-suckers or blanket holders if they didn't attach to a pacifier. Some babies just seem to need security objects, and there isn't a lot you can do about that. Just because you offer a pacifier to your baby, that doesn't mean he will develop a bad habit. I have offered pacifiers to all six of my babies, all took them occasionally, and none of them became attached to them. I did have several children who sucked their thumbs for what seemed like forever, but that's another article.
I think it is great if your older baby will take a pacifier occasionally. If you have ever been driving down the highway with a screaming baby in the backseat and no way to pull over, even though you nursed just before you left, and you KNOW he can't possibly be hungry, you will know what a wonderful thing a pacifier can be (this especially applies if you have older kids and spend half your waking hours car-pooling). Although I have known some large breasted women who could actually lean over the car seat and let their breast hang in the baby's mouth, I have never met one well-endowed enough to sling her breast over the back seat to feed her baby. That's just one example of when a pacifier can be a lifesaver. Another is when your older baby (who is fat and happy and obviously getting enough to eat) has been marathon nursing for hours and nothing is making him happy. Sometimes he just wants to suck himself to sleep, and doesn't want to nurse. Believe it or not, this does happen. He almost gets angry when the milk comes out, and may settle right down with a pacifier. There also may be times when someone other than you may have to soothe your baby, especially if you return to work and he is in day care with other babies. You really can't stick a bottle in a baby's mouth every time he fusses, and caregivers don't have the breast to use as a built in pacifier.
So, I have broken the cardinal rule of lactation counseling by saying that I don't think pacifiers are all bad. This is because I have survived raising six children, and I know that you do whatever works and helps you keep your sanity. This may or may not include bottles, pacifiers, and formula.
There are however, some valid concerns about the use (and abuse) of pacifiers. Aside from the risk of nipple confusion, pacifier use is correlated with early weaning for a variety of reasons. Because newborns love to suck on anything put in their mouth, whether it is a finger or an artificial nipple, they may use the pacifier as a substitute for feedings, especially if they are small, ill, jaundiced, or just have a very laid back temperament. There is a spot in the back of a baby's mouth where the hard palate meets the soft palate. When anything touches it, an automatic sucking reflex is triggered. That's why babies will suck automatically when a finger or a rubber nipple is put in their mouth. The soft, mushy human nipple must be drawn back in the baby's mouth until it hits that spot, so use of an artificial nipple may make him somewhat lazy when it comes to nursing.
Some babies are perfectly content to happily miss a feeding as long as they have something to suck on, and some mothers take advantage of this by plugging their baby's mouth with a pacifier every time he fusses in order to make him sleep longer or go longer intervals between feedings. Young infants should spend their time and energy in nutritive sucking at the breast, not in non-nutritive sucking. Overuse of pacifiers can lead to poor weight gain, plugged ducts and mastitis, and a decrease in milk supply. If you have a yeast infection or your baby has thrush, pacifiers can become contaminated. Boil pacifiers every day during a thrush episode, and throw them away after a week. The same thing applies to bottle nipples.