If you're worried that your baby might suddenly stop breathing during the night, know that the chances of a child succumbing to sudden infant death syndrome (SIDS) — which is defined as the sudden and unexplained death of an apparently healthy infant — are very, very small.

Know too that there are environmental factors associated with an increased risk of SIDS (like tummy sleeping and loose bedding) that you can easily avoid. Here's more on SIDS and what you can do about it as a parent.

What is SIDS?

SIDS stands for sudden infant death syndrome and is the sudden, unexplained death of a baby under 1. SIDS is one of the leading causes of death for infants in their first year of life. The vast majority of cases are tied to sleep.

SIDS is up to 12.9 times more likely to occur in babies who sleep on their stomachs compared to babies who sleep on their backs (though the numbers vary depending on the study), and the incidence of SIDS dropped by about half in countries that made the switch to back sleeping. That's why you should always place your baby on her back to sleep until her first birthday.

What is it about stomach sleeping that's so risky? It makes a baby more likely to rebreathe her own exhaled air, which can lead to a buildup of carbon dioxide and lower oxygen levels. That, in turn, can potentially result in suffocation.

There's more. A baby who snoozes on her stomach tends to have longer, deeper periods of sleep, so she's less likely to rouse or change positions if her airways happen to become blocked during sleep.

Stomach sleepers are also more likely to overheat, experience sudden drops in blood pressure and lose the ability to control their heart rates — all factors that can raise SIDS risk.

What if your little one is rolling onto her tummy mid-snooze? You should still put your baby to sleep on her back, but if she changes positions on her own, it's fine to let her do her thing. Babies who have mastered rolling over and back are at much lower risk for SIDS, experts say.

What causes SIDS?

It isn't fully understood, but experts are learning more and more about SIDS causes. Most used to think healthy babies were affected by SIDS at random. But now researchers have a different leading theory.

Today it's thought that there's no one single cause of SIDS, and that most of the time, multiple risk factors combine to cause a baby who's already at risk for SIDS to die from it.

SIDS babies might have underlying problems that put them at risk for sudden death — even though they might seem perfectly healthy.

For instance, the part of the brain that's supposed to respond to dangerous breathing conditions could be underdeveloped in some babies. One recent study linked SIDS cases with low levels of a particular enzyme involved in the brain's arousal pathway. Another study identified specific genes that could play a role in sudden unexpected deaths.  

These underlying problems certainly don't guarantee SIDS, but they could set the stage if other known risk factors are also in place — like putting a baby to sleep on her stomach. If she were to overheat or re-breathe trapped air, for instance, she might be less likely to wake up and cry or move into a position that would help her breathe better.

On the other hand, experts know a few things about what doesn’t cause SIDS. Vomiting, choking and illness don’t play a role. Immunizations don't, either.

How common is SIDS and what can affect a baby’s risk?

SIDS is scary to think about, and of course, you want to take every possible precaution to protect your baby. Still, know that an infant's SIDS risk is very small.

Today, only 33 in 100,000 babies are affected by SIDS, according to the latest data from the Centers for Disease Control and Prevention (CDC). Tragically, before the launch of the American Academy of Pediatrics’ "Back to Sleep" campaign in the early 1990s, SIDS rates were much higher, affecting around 130 in 100,000 babies.

In 2019, the latest year for which SIDS statistics are available, there were approximately 1,248 SIDS-related deaths, according to the CDC.

In general, younger babies are more susceptible to SIDS than older ones. The peak SIDS age is typically 1 to 4 months, with the vast majority of cases occurring before 6 months. 

Are there any warning signs of SIDS? As unsettling as it is, SIDS can't be caught or predicted ahead of time. But you can protect your baby by avoiding known risk factors, including:

  • An unsafe sleep environment. Infants who sleep on their tummies or sides; sleep with loose bedding, pillows or soft toys; or sleep in a too-warm room may be more susceptible.
  • Unhealthy behaviors during pregnancy or postpartum. Smoking, drinking or using drugs when you're pregnant or after your baby is born can raise SIDS risk. So can exposing your baby to secondhand smoke. 
  • Other factors. SIDS is more common in babies who are born prematurely, have a low birth weight or have a family history of SIDS.

How do you prevent SIDS?

SIDS can't be completely prevented, but there are things you can do to reduce your baby's risk as much as possible. 

Safe sleeping practices are at the top of the list, and setting up a healthy sleep environment is the most effective way to keep your little one protected. Here's what you can do:

Put your baby to sleep on her back every time

Remind other caregivers to do this too. When your little one's awake, practice supervised tummy time to encourage her development and prevent flat spots from developing on her skull.

Use a firm, flat crib mattress, a fitted sheet and nothing else

Keep loose blankets, sheets, quilts, sheepskins, pillows, mattress toppers, soft toys and stuffed animals out of the crib. Those items should wait until your baby is at least a year old. 

Do not use crib bumpers or inclined sleepers. They can raise the risk of suffocation and entrapment, which is why the Safe Sleep for Babies Act recently made manufacturing and selling them illegal in the U.S.

Keep your baby from getting overheated

Use a temperature-appropriate sleep sack or swaddle instead of dressing your baby in extra layers or blankets. As a rule of thumb, dress your baby in up to one more layer than you would wear, and skip hats (unless your baby's just a few hours old or in the NICU). Do not use weighted sleepers or swaddles. 

Avoid keeping the room too warm

Not sure if your little one is getting hot? Touch her tummy or the nape of her neck. If they feel too warm, she's probably too warm. If the temperature is too hot for your little one, you might also notice flushed skin or sweat.  

Stop swaddling when your baby starts trying to roll over

This milestone usually happens around 3 or 4 months, but it can sometimes occur earlier. Swaddling after that point could increase the risk of suffocation, so call it quits as soon as your little one attempts moving from from her back to her front.

Have your baby sleep in the crib, bassinet or play yard whenever possible

If she nods off in the car seat, stroller, swing or carrier, move her as soon as you can. The crib, bassinet or play yard should meet current crib safety standards, set by the Consumer Product Safety Commission (CPSC), and should have no broken or missing parts. 

If you worry that you might nod off during a feeding (it happens) feed your baby in your bed instead of a sofa or cushioned chair, and remove any pillows, blankets and soft bedding. Move your sweetie back to her own sleep space as soon as you wake up, but try to avoid falling asleep during feedings as much as you can.

Offer a pacifier for sleep 

Pacifiers can help reduce SIDS risk, but if your baby doesn’t want one or spits it out, that's okay. Avoid pacifiers that attach to anything. And If you’re breastfeeding, wait until you and your baby both have the hang of it to introduce a paci.

Steer clear of "safe sleep" products

Don’t use wedges or sleep positioners in your baby’s crib. They haven’t been shown to help with SIDS. 

Home cardiorespiratory monitors aren’t beneficial for SIDS either, so you should only use one if your baby has a diagnosed breathing or heart problem and a pediatrician recommends a monitor. Otherwise, they can lead to a false sense of security. 

Share a room

SIDS is less likely to occur in babies who share a room with their parents — but sleep in their own space (like a bassinet) close to their parents' bed. The AAP recommends room sharing ideally for at least the first six months. Avoid bed sharing, which can raise SIDS risk.

Breastfeed, if possible

While safe sleep practices play the biggest role in SIDS prevention, there are other important protective factors too. For example, infants who are breastfed for at least six months are at lower risk for SIDS.

The AAP recommends breastfeeding exclusively for this period, if you can, and then continuing to offer breast milk along with solids until the one-year mark or longer. 

Get your baby vaccinated

Immunizations may offer protection against SIDS, which is just one more reason to stay on top of your baby’s vaccine schedule.

Keep smoke and nicotine away from your baby

Exposure to secondhand smoke raises the risk of SIDS, and so does using alcohol, marijuana, opioids and illicit drugs during pregnancy and after birth. As for e-cigarettes and vapes? They can be harmful too, so you're better off steering clear. 

Can a baby survive SIDS?

Even though the thought can be deeply unsettling, experts agree that there aren't any warning signs for SIDS. And since SIDS isn't diagnosed until after an infant has died and the death has been investigated, you can’t catch SIDS while it’s happening and stop it, for instance, by performing CPR.

The best thing you can do to reduce the risk for SIDS is by following established safe sleep guidelines, as well as keeping your baby away from cigarette smoke, staying on top of vaccinations and breastfeeding if possible.

And while it won't help with SIDS prevention, taking an infant CPR course is still a good idea. In the event of choking, drowning or other serious injuries, knowing how to perform rescue breathing and chest compressions can be life-saving.

What's the difference between SIDS and SUID?

Sudden unexpected infant death, or SUID, is the sudden explained or unexplained death of a baby. Types of SUIDs can include SIDS as well as suffocation, strangulation or choking. The cause of death is said to be SIDS when doctors can’t pinpoint the cause of death even after an investigation.

Like SIDS, SUID doesn't come with any warning signs, but there are things you can do to lower the risk.

When can you stop worrying about SIDS?

It's important to take SIDS seriously throughout your baby’s first year of life. That said, the older she gets, the more her risk will drop. Most SIDS cases occur before 4 months, and the vast majority happen before 6 months.

That said, try not to spend too much time worrying about SIDS, even during your baby’s first few months of life. Practice safe sleep guidelines and other recommended measures, and take comfort in the fact that you're providing the safest possible environment for your little one.

Something else to keep in mind: The breathing control center in your newborn’s brain is still maturing. So if you find that you're devoting a lot of focus to her breathing, it can be helpful to know that some of the things that seem unusual are actually normal.

For instance, a newborn’s breathing rate naturally slows from 40 to 60 breaths per minute while she's awake to 30 to 40 breaths per minute while she's asleep. Rapid, shallow breaths for 15 to 20 seconds followed by a few seconds of paused breathing are also to be expected.

But if at any point you notice something that seems concerning, your pediatrician is a phone call away.

Support for families affected by SIDS

Dealing with a SIDS loss is one of the most heart-wrenching things a parent or family can go through. If you or a family you know has been affected by SIDS or want to work to promote SIDS awareness, consider reaching out to a support group like The Compassionate Friends or Share Pregnancy & Infant Loss Support.

While nothing can fully take away the pain of losing a child, connecting with others who've had similar experiences is often comforting.