What Is Sudden Infant Death Syndrome (SIDS)?

You might have heard of SIDS, a concern for parents of young children. SIDS stands for sudden infant death syndrome. Even though the causes of SIDS aren't fully known, there are steps you can take to create a safe sleep environment for your baby and help prevent SIDS.

Read on to find out more about SIDS, what causes it, the potential risk factors, and how to prevent SIDS.

What Is SIDS?

The definition of sudden infant death syndrome, shortened to SIDS, is an unexplained and unexpected death of an otherwise healthy baby who is less than 1 year old. SIDS is sometimes called crib death because it usually happens when the baby is sleeping.

How Common Is SIDS?

If you’re wondering just how common SIDS is, statistics show SIDS is rare in the United States. Based on data from 2020, the rate of SIDS was 38. 4 deaths per 100,000 live births. This means that SIDS affected under 0.04 percent of all live births in the United States.

What Causes SIDS?

It's not known exactly what causes SIDS, but there may be some environmental factors that make a baby more vulnerable to SIDS, as well as maternal, physical, and general factors that may increase the risk. These risk factors are described in our section below.

SIDS Risk Factors

As mentioned above, here are some of the potential risk factors of SIDS, including environmental, maternal, physical, and general factors:

Sleep Environmental Factors

Some sleep factors that increase SIDS risk include:

• Stomach or side sleeping position. Babies who sleep on their stomachs or sides might have more trouble breathing than those who sleep on their backs.

• Sleeping on a soft surface. Sleeping on a cushy comforter, a soft mattress, or a waterbed can block a baby’s airways.

• Sharing a bed. Sleeping in the same bed as parents, siblings, or pets increases the risk of SIDS because of the potential for blocking the baby’s airways.

• Overheating. Being too warm while sleeping can increase the risk of SIDS.

Maternal Risk Factors

Even before birth, parents-to-be might unknowingly contribute to their baby's SIDS risk. Maternal risk factors include if a pregnant person:

• is younger than 20

• smokes cigarettes

• consumes drugs or alcohol

• has had inadequate prenatal care. That’s why it's important to schedule and go to all your prenatal visits.

Physical Factors

These are some of the physical risk factors that may increase a baby’s risk of SIDS:

• Brain defects. In some babies, the part of the brain that controls breathing and arousal from sleep hasn't matured enough to work properly, making them more vulnerable to SIDS.

• Low birth weight. Premature babies, or those who are twins or other multiples, may not have developed full control over their breathing and heart rate yet, potentially making them more vulnerable.

• Respiratory infection. Having recently had a cold may contribute to breathing problems for babies, which can increase the risk.

General Risk Factors

Although the exact cause or causes of sudden infant death syndrome are unknown, factors such as age may contribute to the overall risk of SIDS:

• Sex. Boys are slightly more likely to be affected by SIDS.

• Age. What age are babies most at risk for SIDS? Infants are most vulnerable between the second and fourth months of life. Many parents wonder "When can you stop worrying about SIDS ? " So, when does the risk of SIDS decrease? The SIDS risk significantly decreases after your baby turns 6 months old and is rolling over, which is a sign they are developing head and neck control.

• Race. Non-white babies are more at risk.

• Family history. There’s a higher risk among babies who’ve had siblings or cousins die of SIDS.

• Tobacco smoke. Babies who live with smokers are at an increased risk.

• Premature birth and low birth weight. Being born early and/or having a low birth weight can increase the risk.

How to Help Prevent SIDS

Knowing how to prevent SIDS and promote safe sleep is important. Take these SIDS prevention tips to help lower the risk:

Do

• Put your baby to sleep on their back. Do this every single time during the first year, and tell anyone else who cares for them that this is a must, whether it’s for a nap or nighttime sleep. A good way to remember is the phrase “Back to sleep. ” Some babies turn onto their stomach or side on their own after being placed on their backs; experts say it's OK to leave them in that position as long as they can roll over both ways without help.

• Keep the crib bare. Make sure the mattress in the crib is firm and fits perfectly without leaving any gaps at the sides. Avoid using any padding, blankets, comforters, pillows, bumper pads, or quilts. Only a tight-fitted sheet should be used—no loose bedding. Never place toys in the crib—not even soft teddy bears. These fluffy surfaces and objects can interfere with your baby’s breathing.

• Move your baby to a firm surface. If your baby falls asleep in the car seat, stroller, or sling, move them to a firm sleep surface as soon as possible. Never put your baby to sleep on a waterbed or a cushion.

• Let your baby sleep in your room. While this depends on your personal preferences, experts recommend your baby sleep in your room with you but alone in a crib. If possible, try this up until they're 12 months old, and consider keeping the crib or bassinet about an arm’s length away from your bed.

• Breastfeed your baby. If you can, breastfeed for at least the first six months. Research suggests this can significantly reduce the risk of SIDS.

• Have skin-to-skin contact. Skin-to-skin contact has many benefits. You can practice it while breastfeeding or bottle feeding, or any other time throughout the day. Your partner can do it, too.

• Offer a pacifier. Sucking on a pacifier at naptime and bedtime might reduce the risk of SIDS. But don't use pacifiers with a strap or string, or ones that attach to clothing. If you're breastfeeding, wait until your baby is 3 to 4 weeks old and you've settled into a nursing routine before offering a pacifier. If the pacifier falls out of your baby's mouth while they're sleeping, don't put it back in.

• Make sure your baby gets all necessary vaccines. Some research indicates immunizations can help prevent SIDS.

• Make sure baby beds and gear are safe. The crib, bassinet, stroller, and play yard should all meet current safety standards. Do not use the item if it’s broken, and if you're borrowing or using a hand-me-down, make sure it meets current regulations.

• Provide tummy time. Give your baby plenty of tummy time when they're awake, as it helps strengthen their neck and back muscles. Remember to supervise tummy time, making sure that your baby remains awake.

Don’t

• Don’t let your baby become overheated. Avoid letting your baby get too hot, as this increases the SIDS risk. Make sure their head isn't covered when you put them to bed. Ensure the air temperature is comfortable for you—make sure it's not too hot. Dress your baby in no more than one extra layer than you would wear, and don't use blankets. Instead, try a wearable blanket or a sleep sack with no hood, or footie pajamas. If your baby's head is hot and sweaty, or if their chest feels hot, they're too warm.

• Don’t sleep with your baby. Sleeping in the same bed as your baby isn't recommended, and here's why: It increases the SIDS risk because you can accidentally roll onto your child as you sleep, and the baby is at risk of becoming entangled in the bedding.

• Don’t rely on a SIDS baby monitor. Experts discourage the use of monitors and other devices that claim to reduce SIDS because they have been found to be ineffective.

• Don’t smoke around your baby. Don't smoke near your baby, and keep your car and home smoke-free, too. Keep your baby away from places where people smoke.

This is a lot to take in, but this slogan might help. Just remember the ABCs of Safe Sleep: Your baby should always sleep

• ALONE;

• on their BACK;

• in a CRIB.

The Bottom Line

SIDS can be worrying for parents, but keep in mind that it's rare. If you follow the safe sleep steps consistently throughout your baby's first year of life, you can help reduce the risk. Remember to put your little one to sleep on their back in their own crib, and ensure the crib is free of blankets, pillows, bumpers, and toys.