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Sudden Infant Death Syndrome: SIDS: Causes & Prevention

Medically Reviewed by Dr. Pierrette Mimi Poinsett, MD
Learn about SIDS and how you can prevent it.

Does the threat of SIDS have you losing sleep?

Do you find yourself watching your baby’s every breath at night and losing out on your own sleep?

This article will teach you everything you need to know about Sudden Infant Death Syndrome (SIDS) and how you can prevent it.

What Is SIDS?

Chances are, you know some things about SIDS already because it is a huge concern for parents everywhere. SIDS, or Sudden Infant Death Syndrome, is a risk for babies who are under the age of 1.

With SIDS, a baby who seems perfectly healthy can go to sleep just like any other night — the difference is they never wake up. They die in their sleep, leaving their devastated families to wonder what happened.

But it’s most common in babies 6 months and younger – 90 percent of SIDS cases happen in this age group (1).

Those most at risk for SIDS are babies between the ages of 1 and 4 months. SIDS is only confirmed after every other possible known cause is ruled out.

What Causes SIDS?

Does the threat of SIDS have you losing sleep? Do you find yourself watching your baby’s every breath at night and losing out on your own sleep? Click here to learn about everything you need to know about what happens when your baby rests its precious head.

There are certain conditions or factors that elevate the risk of SIDS and SUIDS. But before you start having a panic attack because your baby falls into one of these categories, keep in mind the overall risk is still very low.

Here are some of the factors that are believed to increase the risk for SIDS and SUIDS (2):

Premature birth

The brains for premature babies aren’t as well developed as full-term babies’ brains are.

Prevention: Follow your doctor’s instructions carefully, particularly if you are put on bed rest. Delaying birth as long as possible will give your baby the best fighting chance it has.

Sleep Safety

Much of the sleep danger that our babies face come from us parents. We try to make them more comfortable, but our efforts only put them in danger. By following what the experts tell you, you can reduce a lot of the risk.

Prevention: Remove any pillows, bumpers, blankets, or stuffed animals from your baby’s crib.


When babies are around secondhand smoke, their respiratory function is impaired compared to babies who aren’t around smoke (3).

Prevention: Don’t smoke when you’re pregnant or after your baby is born, and don’t hang around with people who smoke around your child.

Delayed or Inadequate Prenatal Care

Visiting your doctor for regular prenatal check-ups can help your child avoid SIDS and SUIDs because doctors will be able to spot any conditions that may cause premature labor. If they can spot it, they may be able to slow it down.

Prevention: Make sure you keep all the prenatal visits your doctor tells you to.

Alcohol and Drugs

Alcohol and drug use during pregnancy is a well-documented SIDS risk for children. When mothers drink alcohol, it can increase the risk for SIDS as well as other reasons for infant death (4).

Prevention: Stay away from alcohol and any illegal drugs while you’re pregnant or breastfeeding. In addition, check any over-the-counter and prescription medication to make sure they are compatible with breastfeeding.


For whatever reason, boys have an increased risk of SIDS. Approximately three out of every five SIDS cases happen to boys (5).

Prevention: You can’t do a thing about this one — the gender of your baby is out of your control.

Recent respiratory infection

Some children who die from SIDS were known to have a viral illness right before they died. That leads researchers to believe there is a link to the two, especially because SIDS seems to be more prevalent during winter months when more respiratory illnesses are circulating (6).

Prevention: Try to protect your baby from germs as much as possible by limiting its exposure to sick people.

Young Maternal Age

Babies who are born to women under the age of 20 are more likely to have SIDS than babies born to older women. That risk climbs if a young mom has more than one child.

Prevention: If you’re under 20 and you have a baby on the way, don’t panic. Your baby will likely be fine. Just make sure you take all of the advice you’re reading in this article.

Being Unable to Breastfeed

Babies who breastfeed are less likely to die from SIDS. Perhaps that’s because breastfed babies have less respiratory illnesses.

Prevention: Your best bet is to breastfeed until your baby is at least 1 year old.

Having Multiples

Multiples, like twins or triplets, have an increased risk of SIDS because they often have low birth weight and premature birth.

Prevention: While it isn’t something parents of multiples should panic about, they should remain vigilant and look for ways to reduce the threat.


Some babies who die from SIDS have an abnormality in the section of the brain that is linked to breathing, body temperature, and heart rate (7). That could be a matter of simple genetics or there could be something else influencing it.

Prevention: There isn’t anything you can do about it. Just relax and take comfort in the knowledge that most babies will be just fine.

A Room That’s Too Warm

If a room is too warm or a baby is overdressed, it may cause an increased metabolic rate in babies, which could cause them to lose control of their breathing.

Prevention: While you don’t want a baby’s room to be too chilly, it shouldn’t be toasty warm either.

Skipping Immunizations

Doing everything you can to avoid illnesses for your baby is a good starting point when it comes to avoiding SIDS. Getting the proper immunizations can help achieve that goal.

Prevention: Make sure you understand which immunizations are required at what times for your baby, and stick to that schedule.

What Doesn’t Cause SIDS

It can be tempting to try to link anything to SIDS, especially because of how random it appears to be. It’s hard not to wonder about what could cause a seemingly perfectly healthy baby to suddenly die.

It’s natural to want to try to find a cause for it, or pin it on some change in schedule or diet.

While you may not be able to figure out everything that can contribute to the risk of SIDS, you can safely rule a few factors out. There are some things that do not cause SIDS that parents might secretly wonder about. They include (8):

  • Medication: Medication is not believed to cause SIDS.
  • Contagions: SIDS is not contagious from child to child. Even if viruses play a small role in SIDS — which hasn’t been determined yet — most children who get viruses don’t die from SIDS. So there are other factors that account for it.
  • Vaccines: While many parents are leery about the perceived harmful consequences of vaccines, SIDS is not caused by vaccinations. Since most infants do receive a series of vaccinations around the same time as SIDS occurs, it’s easy to understand why grieving parents might link the two. But studies have shown no spike in SIDS caused by vaccinations (9).

How to Prevent SIDS

Now that you know what factors may increase your child’s risk of SIDS or SUIDS, you need to know what safety tips to follow so you can be proactive about making your child’s slumber as safe as possible.

There’s nothing you can do to completely safeguard your child’s health. That’s a painful truth to realize as parents. We want to protect them from everything, but we simply can’t.

The best we can do is learn all about the hazards they face and try to mitigate them as much as possible. Education really is our best bet.

But, luckily, there are some measures we can take to increase the odds they won’t end up succumbing to SIDS or other sleep-related hazards.

1. Put Your Baby on Their Backs When They Sleep, Even at Naptime

Since the American Academy of Pediatrics began recommending babies sleep on their backs instead of their stomachs in 1992, the incidents of SIDS has decreased by over half. Sleeping on their backs makes a baby less likely to get overheated and gives them a greater amount of fresh air to breathe.

Side sleeping should be discouraged until your child is old enough to roll over on their own. At that point, always start your child off on their back, but if they roll to their side, you don’t have to move them back into the back position.


Sleeping on the stomach should be avoided. Tummy time is important, but only during your baby’s waking hours while you’re supervising.

2. Don’t Cover Your Baby’s Face or Head While Sleeping

It’s essential your baby have fresh air circulating while they’re sleeping. If they have a blanket covering their face, they’ll have less access to the fresh air they’ll need. That’s a dangerous situation for a baby, particularly one that may still be a little stuffy from a recent illness.

3. Put Your Baby In a Correct Sleeping Location

Babies often fall asleep in the strangest places — that’s because they tend to sleep a large part of their day. Here are some of their favorite spots to snooze.

  • Cribs: A crib is the safest spot for a baby to sleep. Use a firm crib mattress and don’t worry about how hard it seems to you — babies have no problem with it.
  • Bassinet: Bassinets are fine for infants, but they shouldn’t be used for older babies. Only use them until your baby starts to roll or move around more. That is somewhere around the age of 4 months.
  • Co-sleeper: Co-sleepers are a relatively new piece of baby gear, but they seem to be just fine, provided they are used correctly.
  • Baby swing: Babies do sometimes fall asleep in their baby swings and moms are often reluctant to move them for fear of waking them and destroying their few minutes of peace and quiet. Doctors do recommend moving babies from the swing to their crib if they fall asleep there.
  • Hammock: Hammocks aren’t recommended for babies to sleep in because they could roll into an unsafe position. If you’re supervising your baby during a day nap, a hammock is fine to use, but it should never be used for unsupervised sleep (10).
  • Couch: Couches are never a safe option for your baby. They can roll over and fall off, and they can sink in some if the couch is too fluffy. That can cause a breathing issue.

4. Share a Room

The American Academy of Pediatrics now recommends room-sharing until a baby reaches a minimum of 6 months old. But doing it until a baby turns 1 year old is even better, they say.

But a baby should have their own place to sleep, like a crib, or a co-sleeper that attaches to your bed, or a bassinet. Putting a baby in your bed is a huge suffocation risk.

5. Avoid Bed Sharing

Putting your baby in your bed may feel good to you. You’ll get their snuggles all night long and be able to keep a close eye on them. But the suffocation risk is too great in your bed.

Your blankets could cover your baby’s face, your pillows could cut off their air supply, and you could roll over on them accidentally in the night.

While some parents have successfully shared a bed with their baby, this is not something you want to try on a whim.

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6. Use Safe Sleeping Gear

When selecting a crib or bassinet, it’s important to err on the side of safety. Think long and hard before you buy a secondhand crib or bassinet, especially if it’s considerably old. We know a lot more today about sleep safety than they did generations ago when they made some of those items.

Any crib should have rails and it should not have a folding or drop down side. Slat distance is also important. The distance between slats must be no more than 2-3/8 inches (6 centimeters) to protect infants from falling out and toddlers from trapping their head between the slats

Whether you decide where to put the crib, either in your room or your baby’s nursery, keep it away from heaters, windows, and dangling cords.

7. Use a Firm Mattress With a Fitted Sheet

The mattress you’ll use for your baby must be firm because that’s the safest option. It should fit snugly into the crib leaving little space between the sides of the mattress and the rails of the crib.

The only piece of bedding you need is a fitted sheet. It must fit tightly onto the mattress.

One of the most common mistakes parents make when setting up their child’s crib is by using bumpers. Bumpers are not only unnecessary, but they pose a suffocation and strangulation risk for your child as well.

8. Leave Those Toys Out of the Crib

Keep the stuffed animals out of your baby’s crib. They may look cute, but safety is more important any day than the cute factor. At their age, those stuffed animals serve absolutely no purpose in their cribs.

This also includes toys attached to pacifiers. Those aren’t safe, especially in the first 4 month window.

9. Dress Your Baby Properly While Sleeping

Don’t keep your baby’s room too warm – they shouldn’t get overheated. Their room should be cool enough that you don’t feel hot when you go in there. A temperature of 68 degrees is good for sleeping.

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10. Sleep Sacks — Like Infant Sleeping Bags

Go with a sleep sack over a blanket. Swaddling with a blanket is a popular method of keeping a baby warm at night. But it’s better to use a wearable blanket like a one-piece sleeper or a sleep sack. Below is an example of a sleep sack.

11. Stop Swaddling By 2 Months

Some moms still love to swaddle their babies. Swaddling is when you wrap your baby tightly up in a blanket. (Learn how to swaddle here)

But if you do opt to swaddle your baby, you should stop swaddling by the time they are 2 months. You don’t want them rolling over and compromising their airways because they’re too tightly wrapped.

12. Consider Using a Pacifier

Pacifiers cut down on the risk of SIDS. But don’t attach the pacifier to your baby’s clothes while it is sleeping. Also, do not attach the pacifier to a string or necklace to decrease the risk of strangulation.

And if the pacifier falls out of your baby’s mouth while they are sleeping, there’s no need to put it back in.

13. Avoid Special Products That Promise to Cut Back on SIDS

Items like sleep positioners are unneeded and potentially dangerous. Wedges placed around your baby to help them maintain a certain position during sleep is never a good idea.

Cardiorespiratory monitors are another product touted to reduce SIDS in babies, but evidence shows they don’t work.

14. Twins Need Enough Sleeping Space

It can be cute to watch your twins cuddled up together while they’re sleeping. But babies still need their own space to cut down on suffocation risks.

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15. Make Sure Caregivers Are Onboard

If your baby is going to a daycare, homecare or staying with a relative when you go back to work, or if it’s just an occasional babysitting day, you should review the ground rules with the caregiver. That can be especially important if the caregiver isn’t a mom or if she’s an older mom, like a grandma.

Since the safe sleeping rules were changed 25 years ago, if this is a woman’s first grandchild she might not know that babies are supposed to sleep on their backs now instead of their tummies.

And caregivers who aren’t moms and might just be filling in for a regular caregiver may not have any idea that it even matters which position a baby sleeps in. You can’t count on anyone to know how to best take care of your baby if you don’t give them instructions on how to do it.

Pro Tip

If the babysitting is occurring away from your home, you should ask to check out where your baby will be sleeping. Stress the importance of back sleeping, not having pillows, stuffed animals, or any other suffocation hazards near your baby.

Sudden Infant Death Syndrome FAQs

Some of the most frequently asked questions about SIDS.

What’s the Difference between SIDS and SUID?

The nursery is one of the top spots where an SUID can occur. SUID stands for sudden unexpected infant deaths. An SUID is when a death happens to a baby who is less than 1 year old and there is no cause of death that can be discovered immediately.

There are three main categories of SUID:

  • SIDS.
  • Accidental suffocation or strangulation in bed, which is broadly known as fatal sleep incident.
  • Unknown causes.

In 2015, approximately 1,600 children died because of SIDS. Another 1,200 babies died from unknown causes, and approximately 900 more died because of accidental suffocation or strangulation while they were in bed.

In recent years, SIDS has continued on a downward trend from a high of 130.3 deaths per 100,000 live births in 1990. The rates have continued to drop in the years since then and were at 39.4 deaths per 100,000 in 2015.

But unlike SIDS, the number of deaths per 100,000 live births have begun to increase in recent years for both unknown causes and accidental suffocations. Because of the increases in both these categories, the overall SUID rate increased from 87.5 deaths per 100,000 births in 2014 to a higher number in 2015 of 92.6 deaths per 100,000 births.

Does SIDS Have a Genetic Predisposition?

If you’ve had a child who died from SIDS, obviously you’ve been through an extremely traumatic event. It’s only natural for you to be over-the-top worried for any future children you have.

Doctors don’t know if the risk is elevated for siblings of a child who died of SIDS. But they do believe that one gene mutation is not the cause for all cases of SIDS (11). They do wonder if there are genes that predispose children to SIDS when combined with other risk factors.

Learn All You Can

There is no way to completely eliminate the risk of SIDS so you’ll still undoubtedly feel worried about it happening again. The best thing you can do is to educate yourself about what you can do to reduce the risk as much as possible.

Do Certain Ethnicities Have Higher SUID Rates?

Certain nationalities do have higher SUID rates than others do. From 2011 to 2014, here are the SUID rates per 100,000 for various nationalities.

  • 194.1 for American Indian/Alaska native.
  • 170.2 for non-Hispanic black infants.
  • 83.8 for white infants.
  • 51.1 for Hispanic infants.
  • 32.7 for Asian/Pacific Islander infants.

SIDS caused nearly half of the deaths of the SUIDs for every racial group, ranging from 44 percent to 52 percent.

The smallest percentage of death for all groups came from accidental suffocation and strangulation while in bed.

Where to Touch Baby to Make Them Sleep?

A lot of babies think it’s really comforting to have their heads stroked slowly while they’re falling asleep. You can also try gently stroking your baby’s back. Try letting them lay on their stomach while you rub their head and back.

Is It Ok to Fall Asleep With Baby on Chest?

We absolutely do not recommend falling asleep with your baby on your chest. There is just too great a risk that you could roll over and crush your baby, or they could fall, or something could happen while you’re asleep.

It’s good for babies to sleep on your chest while you’re awake to supervise them, but make sure you won’t fall asleep, too.

Will Baby Choke If Sleeping on Back?

No, babies won’t choke if they sleep on their backs. In fact, sleeping on their back means their trachea (air tube leading to the lungs) is on top of the esophagus (food tube leading to the stomach.)

Even if your baby spits up in their sleep, their trachea knows to block the airway so nothing trickles into their lungs.

What is the Safest Way to Co Sleep With a Newborn?

The safest way to sleep with a newborn is by placing them in their crib or cradle while you fall asleep in your bed. It just isn’t safe to sleep in the same bed as your newborn because they could easily get crushed.

Sleeping in a crib or cradle protects them and keeps them from falling.

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Headshot of Dr. Pierrette Mimi Poinsett, MD

Medically Reviewed by

Dr. Pierrette Mimi Poinsett, MD

Dr. Pierrette Mimi Poinsett is a veteran licensed pediatrician with three decades of experience, including 19 years of direct patient clinical care. She currently serves as a medical consultant, where she works with multiple projects and clients in the area of pediatrics, with an emphasis on children and adolescents with special needs.