Babies are adorable, sure, but they're notorious for their disgusting bodily fluids. Things like spit up and poop can happen without notice, leading to catastrophic messes us parents would love to forget. So with all those questionable fluids flying around, it's normal to ask questions like, "Is it OK if baby spits up in his sleep?" Thankfully the answer is pretty clear and should provide new, sleep-deprived parents with some peace of mind.
According to The Baby Sleep Site, babies spit up when they're tying to figure out how to feed. The site adds that the frequency in which a baby spits up will lessen with age and as a baby's digestive track matures, usually between 12-18 months of age. When it comes to how much spit up is normal, as long as your baby produces wet diapers and is gaining weight, they're probably OK.
So how about when they're sleeping? More importantly, it safe to let a baby sleep on their backs, even if spit up is involved? Dr. Laura A. Jana, MD, FAAP and Dr. Jennifer Shu, MD, FAAP, co-authors of Heading Home With Your Newborn, claim babies who sleep on their backs not only reduce the risk of Sudden Infant Death Syndrome (SIDS), but those babies also instinctively know how to turn their heads to protect the airways from blockage.
In fact, this claim is back by the National Institute of Child Health and Human Development (NICHD) via their "Safe to Sleep" campaign, that promotes the American Academy of Pediatrics' (AAP) guidelines for safe infant sleep practices. The NICHD states that babies who spit up in their sleep will cough up, or swallow, whatever's in their mouths, echoing the sentiment that a baby's instincts take over to keep their airways clear. They also recommend laying baby on his, or her, back to trigger this natural response (as well as prevent the risk of SIDS).
The Baby Center advises burping to help prevent spit up, though they add it's OK if you have a baby who doesn't always need to. The use of a crib wedge or propping the mattress just slightly is suggested for more serious spit up, such as GERD or reflux — which your baby will need specific medical testing to diagnose. These medical conditions should be diagnosed by a pediatrician before parents decide to implement any new sleeping practices.
The bottom line is this: a baby spitting up while sleeping, though messy and gross, doesn't seem to be a danger. As long as you're taking all the precautions to keep your baby sleeping in a safe environment, there isn't much to worry about unless your baby shows signs of something more serious. Then, as stated previously, it's time to talk to your pediatrician before you make any changes.