Sudden unexpected infant deaths (SUIDs) – including those caused by SIDS – happen without warning, making them particularly devastating for families. Lower your baby's risk with safe sleep practices: put her to bed on her back, provide a firm sleeping surface free of soft items and bedding, and sleep in the same room (but not in the same bed) as your baby.
What is SIDS?
Sudden infant death syndrome (SIDS) is the diagnosis given when a child under 1 year old dies suddenly and an exact cause can't be found after a death scene investigation, an autopsy, and a review of the child's medical history. SIDS falls under the diagnostic category of sudden unexpected infant deaths (SUIDs), which typically occur during sleep or in a baby's sleep area. SUIDs also include deaths from accidental suffocation or strangulation, and from unknown causes.
SIDS is the leading cause of death in the United States for babies between 1 month and 1 year old, and 90 percent of SIDS cases involve infants younger than 6 months.
According to the Centers for Disease Control and Prevention (CDC), of the 3,600 SUIDs that occur in the United States each year:
- 1,400 babies die from SIDS
- 900 babies die from accidental suffocation or strangulation while sleeping
- 1,300 babies die during sleep for unknown reasons
Note: There is some overlap among these three subsets while experts work on stricter definitions. More deaths that would have been attributed to SIDS in the past are now being classified as accidental suffocation or strangulation.
While SIDS can occur outside of cribs, it's also known as "crib death" because it happens most often during the night, usually between 8 p.m. and 8 a.m. Nighttime isn't the only time that SIDS strikes, however.
About 15 to 20 percent of SIDS deaths happen in childcare settings. This is a surprisingly high number considering that babies spend much less time sleeping at daycare than they do at home. This statistic points out how crucial it is to make sure that everyone who cares for your baby follows safe sleeping guidelines, including not using a sitting device, such as a car seat or stroller, as an alternative to a crib (see "How can I reduce my baby's risk of SIDS and other sleep-related dangers?" below).
What causes SIDS?
Researchers have learned a great deal about SIDS, but they still have no definitive answer to what causes it.
Most experts believe that SIDS occurs when a baby has an underlying physical vulnerability (such as immature or abnormal functioning of the heart, breathing, or arousal) and is exposed to certain stressful factors (such as sleeping tummy-down or being dressed too warmly) during a critical period of development.
Recent research suggests that inadequate levels of the brain chemical serotonin can make an infant more vulnerable to SIDS. Experts found that up to 70 percent of babies who died from SIDS had lower than normal levels of serotonin in the brain stem. Serotonin helps regulate breathing, heart rate, and blood pressure during sleep.
Experts are continuing to study the brain, the autonomic nervous system, infant care and sleep environments, infection and immunity, and genetics in search of answers.
Are certain babies at a higher risk for SIDS?
Yes. Risk factors include:
- Preterm birth. The earlier a baby is born, the higher the risk of SIDS.
- Low birth weight. The lower a baby's birth weight is, the higher the risk of SIDS.
- Younger than 4 months.
- Being a boy. About 60 percent of SIDS victims are boys.
- Being a twin. Twins have double the risk of SIDS, which is largely due to the overall lower birth weight of twins.
- Mother under the age of 20.
- Mother who smoked during pregnancy.
- Short span between mother's pregnancies.
- Sibling who died of SIDS.
- Certain ethnic backgrounds. SUIDS rates were highest for Native American/Alaska Native and non-Hispanic black infants (more than twice those of non-Hispanic white infants) between 2013 and 2016, according to the CDC. Research indicates that these higher rates are related primarily to infant care practices such as a preference for bed sharing or placing infants on their stomach to sleep.
Why does sharing a bed with my baby raise the risk of SIDS and other sleep-related dangers?
For one thing, your bed has pillows and soft bedding, which are risk factors for SIDS. It's also easier for your baby to become overheated while sharing your bed.
If you're feeding your baby in your bed and concerned that you might fall asleep, strip the bed clear of pillows and bedding (a tightly fitted sheet is okay). If you fall asleep, put your baby in her crib when you wake up.
In addition to the risk factors above, studies have shown that these bed-sharing situations are especially dangerous for a baby who is:
- Placed on soft bedding such as pillows or blankets
- Placed on a soft surface such as a couch, armchair, or waterbed
- Sharing with someone who is very tired or using medication that makes it hard to wake up
- Sharing with a smoker, even if that person isn't smoking in bed
- Sharing with someone who drank alcohol
- Sharing with someone who took illicit drugs
- Sharing with anyone who is not a parent, including other children
- Sharing with more than two people
Find out more about the dangers of bed sharing.
How can I reduce my baby's risk of SIDS and other sleep-related dangers?
There's no guaranteed way to prevent SIDS, but you can greatly reduce the risk by following these safe sleep recommendations from the American Academy of Pediatrics (AAP). Following these recommendations will also reduce your baby's risk of other types of sleep-related death, including suffocation, strangulation, and entrapment.
Put your baby to sleep on her back. This is one of the most important things you can do to help protect your baby.
The AAP began recommending that infants be placed on their backs for sleep in 1992, and the Back to Sleep (now known as Safe to Sleep) campaign began in 1994. In response, the rate of deaths from SIDS dropped from 130 per 100,000 births in 1990 to about 35 per 100,000 births in 2017.
A baby's risk of SIDS has been found to be two to 13 times higher (depending on the study) if she sleeps on her tummy instead of her back. When a baby sleeps tummy-down, she's more likely to overheat, have pauses in breathing and fewer arousals, and rebreathe the air she has just exhaled, which contains less oxygen.
- In addition to putting your baby to sleep on her back during the first year of her life, make sure that every caregiver, including relatives, babysitters, and childcare providers, knows to do this.
- Don't put your baby to sleep on her side. Babies placed on their side can easily end up on their tummy.
- Don't use towels or a sleep positioner to try to keep your baby on her back. The Food and Drug Administration (FDA) and Consumer Product Safety Commission (CPSC) issued a warning to parents to stop using sleep positioners after 12 infants suffocated while using these devices.
- Once your baby is strong enough to roll over by herself, you don't have to worry about her staying on her back all night. But continue to place her on her back when you lay her down for sleep until she's 1 year old.
One problem with putting your baby on her back so much is that she may develop a flat spot on the back or side of her head. This is called positional plagiocephaly, or "flat head syndrome." (See tips on ways to prevent plagiocephaly, such as supervised tummy time.)
Don't share a bed with your baby because it's associated with a higher risk of SIDS and accidental suffocation, strangulation, or entrapment.
The AAP recommends that your baby sleep in your room, but not in your bed, at night for at least the first six months and ideally for the first year.
Positioning a crib, bassinet, or play yard close to your bed allows you to easily reach your baby for nighttime feedings and comforting. This arrangement cuts the risk of SIDS by as much as half, according to the AAP.
Do not put any blankets or toys – especially soft ones like stuffed animals – in the crib. Keep any other item that could cover your baby's face, neck, or head out of the crib.
Read more about the dangers of bed sharing.
Choose a safe crib, bassinet, or play yard. Many used cribs do not meet current safety standards.
Millions of cribs by major brands have been recalled in recent years.
See our article on how to buy a crib for guidelines on choosing a safe crib. Also read our tips for childproofing your nursery to keep your baby's sleeping environment free of hazards.
If you'll be traveling, make sure the place you're staying has a safe crib, or bring a portable crib or play yard with you.
Use a firm sleeping surface that's free of soft bedding and pillows.
Put your baby to sleep on a firm, flat mattress with only a fitted sheet under him. (It's okay to put a thin, tight-fitting mattress pad under the sheet to protect against diaper leaks.)
- Don't use a soft mattress, such as one with memory foam, or any kind of mattress topper. Soft surfaces increase the risk of suffocation if your baby ends up in the tummy-down position. If your baby sleeps in a play yard or bassinet, use only the pad that comes with it and don't cover it with any cushions or extra padding.
- Don't use crib bumpers, which the AAP and SIDS-prevention groups caution against. There's no evidence that bumpers prevent injuries, and they may lead to suffocation, strangulation, or entrapment. Also, without bumpers, air circulates more freely around your baby and you can see him better.
- Don't cover your baby with a blanket or bedding of any sort because it can end up over his face and can obstruct his breathing. You can swaddle your baby, (see “Is it okay to swaddle my baby below?”), but if you think your baby is chilly, dress him in warmer clothing such as footed pajamas. Or put him in a cotton one-piece and zip him into a wearable blanket or sleep sack – a sleeveless garment that's closed along the bottom like a bag. (Get more ideas for keeping your baby warm at night without blankets.)
Keep the crib empty.
Do not put any toys – especially soft ones like stuffed animals – in the crib. Keep any other item that could cover your baby's face, neck, or head out of the crib.
Avoid falling asleep with your baby on a couch, armchair, or any other soft surface.
These cushioned environments are dangerous for infants because of the increased risk of SIDS or suffocation, according to the AAP. Because it's so easy to nod off when you're sleep deprived, avoid holding or feeding your baby while sitting or reclining on plush furniture. It's safer to bring your baby into a bed that's stripped of bedding, including blankets and pillows, than to risk falling asleep in a soft armchair. If you happen to fall asleep in bed with your baby, put her in her crib as soon as you wake up.
Don't let your baby sleep in positions that could affect her breathing.
The AAP recommends against letting babies sleep on an incline, a position that could cause your baby's airways to be blocked, preventing him from breathing properly.
- The safest sleep position for your baby is flat on his back – this keeps his airway open. (And don't worry, he won't choke or gag while on his back, even if he has gastroesophageal reflux disease, or GERD.)
- Don't let your baby sleep for extended periods in a sitting device – including a car seat, stroller, swing, or bouncer – and never in an inclined sleeper. This is particularly important for babies under 4 months because they can suffocate if they sleep in an inclined position and their head rolls forward too much. If your baby falls asleep in a sitting device, transfer him to a crib, bassinet, or play yard as soon as is practical.
- When your baby is in an infant carrier or sling, make sure his head is up above the fabric with his face visible, and his nose and mouth are clear and not pressed against your body or the fabric.
- Don't prop up your baby's mattress with a towel or a crib wedge in an attempt to relieve congestion or reflux. He could slide or roll down into a position that could make it difficult for him to breathe.
Avoid overheating your baby.
Overheating is a SIDS risk factor. To prevent it:
- Dress your baby for sleep in no more than one layer more than an adult would wear to be comfortable in that environment.
- Watch for signs of overheating such as sweating, damp hair, or a chest that feels hot to the touch.
- Don't cover your baby's face or head with a hat or hood when he's sleeping. (Unless your baby is premature, he won't need a cap after the first few days.)
Get regular prenatal care.
Several studies link regular prenatal care to a lower risk of SIDS. Proper prenatal care is not only important in ensuring a smooth pregnancy, it also protects your baby's health by reducing the risk of a premature birth or low birth weight (both of which are risk factors for SIDS).
Don't smoke, drink alcohol, or use illegal drugs during pregnancy.
Smoking during pregnancy is a risk factor for SIDS. An analysis of CDC data found that any maternal smoking during pregnancy more than doubles the risk of SUID. Drinking alcohol and using drugs during pregnancy are also risk factors. All three can compromise a baby's healthy development in many other ways too.
Keep your baby away from cigarette smoke.
Keep the air around your baby at home, in the car, and in all other environments free of smoke. If others insist on smoking, make sure they do it away from your baby. If you need help quitting yourself, read about how to stop smoking after your baby is born and talk to your doctor.
Studies show that a baby's risk of SIDS rises with each additional smoker in the household, with the number of cigarettes smoked around her each day, and with the length of her exposure to cigarette smoke.
Make sure your baby gets all recommended immunizations.
Evidence suggests that getting all of the vaccines on the recommended schedule may help protect against SIDS.
Breastfeed if you can. Giving your baby any amount of breast milk is a positive, and the more you can exclusively breastfeed, the more protection your baby has against SIDS.
A meta-analysis concluded that babies who were breastfed for at least two months cut their risk of SIDS in half, even if the babies were not exclusively breastfed. Breastfeeding for longer than two months provided increased protection.
Offer your baby a pacifier when you put him down to sleep.
Studies show a lower incidence of SIDS among infants who use pacifiers, although experts don't know whether there's a direct cause and effect. Because of the correlation, the AAP suggests that you give your baby a pacifier when putting him down for naps and at bedtime for the first year of life.
The AAP cautions that, if you're nursing, it's best to wait to offer a pacifier until breastfeeding is well established – usually around three or four weeks after birth.
You don't have to reinsert the pacifier if your baby drops it once he falls asleep. And there's no need to force your baby to use one if he doesn't take to it.
Note: To avoid strangulation, don't hang the pacifier around your baby's neck or attach it to his clothing while he's asleep.
Does my baby have to sleep in a crib?
The AAP recommends that your baby sleep in a crib, bassinet, or play yard that meets current safety standards and that is placed in your room close to your bed.
- Do not use any sitting device as an alternative to a crib, and make sure that childcare providers and babysitters do the same. If your baby falls asleep in a car seat, stroller, bouncer, or swing, move her to a crib, bassinet, or play yard as soon as practical. (Consider bringing a portable crib or play yard with you if you're going somewhere without a crib.)
- Do not use an inclined sleeper. The CPSC has announced recalls for more than 5 million inclined sleepers, including the Fisher Price Rock 'n Play and Kids II Rocking Sleepers.
- The AAP says it cannot make a recommendation for or against a bedside sleeper – a criblike bed that fits snugly against your bed – because of the lack of safety studies. However, the CPSC has developed safety standards for bedside sleepers, so before you purchase one, be sure to check that it meets these standards.
- The CPSC has not developed safety standards for in-bed sleepers, products designed to give an infant a separate space in an adult bed, for example, by using padding or a mesh structure as a barrier. "There is no evidence that these devices reduce the risk of SIDS or suffocation, or are safe," according to the AAP Taskforce on SIDS.
Is it okay for my twins to sleep together?
The AAP recommends that twins or other multiples not sleep together. There isn't data specifically addressing bed-sharing multiples, but other studies have shown that bed sharing with other children places an infant at a higher risk of SIDS. And multiples are likely to have other risk factors for SIDS, such as premature birth and low birth weight.
Is it okay for me to swaddle my baby?
Yes, as long as you stop as soon as your baby starts trying to roll over or is able to get out of the swaddle. These scenarios can cause him to get unsafely bound up in the swaddle, have his face covered, or suffocate in the face-down position.
Some SIDS experts caution that swaddling could contribute to overheating. So if you do swaddle your baby, use a thin blanket and make sure the room isn't too warm.
Should I use a heart rate monitor to prevent SIDS?
According to the AAP, there's no evidence that cardiorespiratory or home sleep monitors (which detect a baby's movement and alert you if it stops for a certain amount of time) reduce a baby's risk of SIDS, and the organization doesn't recommend their use for this purpose. They could also provide a false sense of security.
An exception is if your baby's doctor has prescribed a cardiorespiratory monitor, which may happen if your baby has a condition like sleep apnea or a slow heart rate. If such a monitor was prescribed for your baby, use it diligently.
Where can I get more information about SIDS?
- The American SIDS Institute conducts research and offers education and round-the-clock support to pediatricians and families. Call (239) 431-5425.
- The Safe to Sleep campaign, sponsored by the National Institutes of Health, offers information, support, and referrals. Call (800) 505-CRIB (2742).
- First Candle provides information and supports research aimed at preventing SIDS and stillbirth. It also offers grief counseling to those affected by the death of a baby on a 24-hour hotline at (800) 221-7437.