Parenthood is weird, and the sheer strangeness of it all is made all the more obvious by the fact that you can stare at a baby's face for hours, completely content. Every slight facial expression is riveting. Sometimes you're convinced you'll explode from all the cuteness. And then your baby does something weird and you're just at a loss. Like that bubble thing. I mean, honestly, why does my baby make bubbles in their sleep? Turns out, it's pretty normal. Again, and always, it can't be understated how weird parenthood is, you guys.
When we're talking about blowing bubbles, we don't mean the kind that come out of jar with a cute wand. Some people refer to it as a frothy substance that comes out of their baby's mouth. Others say it looks like spit in the corners of their baby's mouth. The one thing these descriptions have in common is a lovely thing called saliva (so, no, it is not caused by soapy milk). According to the University of California San Francisco's website, a baby's salivary glands start developing when they're around 2 months of age. The site Baby Center also states that babies begin drooling from around the 2 month mark. (So now we know what accounts for all that extra saliva in those delightful nighttime bubbles. Perhaps science is just as strange as parenthood. Perhaps.)
Blowing bubbles is a normal part of development for many babies. According to the site Healthy Children, blowing bubbles and drooling happens a lot during this stage of development because so much of how babies get what they need is centered on the mouth.
Increased drooling and saliva bubbles could be an early sign of teething, too, depending on your baby's age. As The Mayo Clinic states on its website, babies often begin teething by about age 6 months, with the two bottom teeth being the first to appear. However, as the site Healthy Children notes, if the drooling seems excessive, or if your baby appears to be ill, it is best to check with your child's doctor to rule out something else (such as your baby having trouble swallowing, or possible gastrointestinal problems).
Babies might start inadvertently making little foamy mouth bubbles around 2 months of age, but they start blowing the "on purpose" kind of bubbles we call "raspberries" between when they're around 6-8 months of age. Some experts say that a child's ability to blow mouth bubbles (or "raspberries") is a sign of early speech and language development. As speech and language pathologist Amy Chouinard tells Fit Pregnancy, "It shows the child is experimenting with his mouth, which goes hand in hand with speech development." Of course, the bubbles your baby makes while they are sleeping are likely not meant to communicate anything to you, at least on a conscious level.
In short, the increased saliva that begins appearing around the 2 month mark is the reason your baby can make those bubbles in the first place. Your baby is also experimenting with new facial movements and new motor skills, essentially putting that saliva to work. If the bubble-blowing during sleep isn't waking your baby up, then the only downside to it all is your picture-perfect photo op being a little more, well, foamy and bubbly looking.