No one knows.
There, satisfied? I’m guessing not. Seriously, though, it can be difficult to pinpoint why babies come down with thrush.
There are some things we know for sure concerning thrush. We know that thrush is an overgrowth of the yeast, called candida, found in every person’s body. We know that infants are more susceptible to thrush because their immune systems aren’t fully developed and they are in the process of developing a healthy balance of fungi and bacteria in their bodies. As far as why certain babies get thrush while others do not, there are a lot of uncertainties.
Some say thrush is caused when an infant sucks too much on a pacifier or bottle. This can happen for one of two reasons. Either the nipples on the pacifier or bottle were not properly cleaned and harbored yeast, or the excessive sucking caused cracks on the inside of the infant’s mouth, creating a perfect environment for the infection. Sounds logical enough, until you discover that some exclusively breastfed babies who do not take a pacifier get thrush.
Others say thrush is contracted when an infant comes into contact with yeast in its mother’s birth canal. This definitely makes sense, and yet some babies are thrush-free until they are 8 months old. It’s unlikely that an infant getting thrush for the first time at 8 months of age contracted it during labor and delivery.
Another possible culprit is the use or overuse of antibiotics. Antibiotics kill bad bacteria, but they also kill good bacteria, therefore upsetting the body’s natural balance. Also a logical explanation, but what if your baby has thrush and has never been on antibiotics?
Better yet, what if your baby is bottle fed, has a pacifier in his mouth all day long, passed through your birth canal when you had a yeast infection, took antibiotics, and never came down with thrush?
As you can see, you might never know why your baby came down with thrush. It’s good to know possible reasons, because it might aid in the prevention of another case of thrush. However, don’t lose any sleep by thinking it was caused by some negligence on your part. Some parents who do everything “right” still have children who come down with thrush.