The Dangers of Sudden Infant Death Syndrome (SIDS)

Sudden infant death syndrome (SIDS) refers to the unexpected, unexplained death of an infant less than 1 year old. It’s one of the leading causes of death for babies in the U.S. Most SIDS deaths happen when the baby is sleeping, and some people still refer to SIDS as “crib death.” For a diagnosis of SIDS, the cause of death remains unclear even after a complete investigation.

Experts believe genetic changes or brain abnormalities at certain developmental stages can make some babies vulnerable to SIDS. A safe sleeping environment, including placing babies on their backs to sleep, helps to prevent SIDS.

Causes

The exact cause of SIDS remains unknown, but researchers have a number of theories.

A growing body of research suggests that infants who die from SIDS have brain abnormalities or defects since birth. These defects are often found in the part of the brain that controls:

• Breathing
• Blood pressure
• Heart rate
• Waking from sleep

Researchers believe that in addition to brain abnormalities, other events must occur for an infant to die from SIDS. Scientists describe this using a triple risk model.

Under this model, three factors all have to occur at once for an infant to die from SIDS. Having only one factor occur may not result in death from SIDS, but if all three occur, the chance of death from SIDS is higher.

The three factors include:

• An at-risk infant: This includes an infant who may have an unknown problem, like a brain defect or genetic change.
• Time in infant’s development: In the first six months of life, infants experience multiple quick phases of growth, which change how well the body regulates itself.
• Environmental stressors: Examples include being overheated, being placed on the stomach to sleep, and being exposed to cigarette smoke.

All three factors need to occur for SIDS to be considered the cause of death.

Infants who don’t have either of the first two factors may be able to overcome any environmental stressors and survive, but infants who may have an unknown problem, together with body systems undergoing a change, may not be able to handle such stressors.

Because the first two factors are unseen, eliminating external risk factors, or environmental stressors, is the most effective way to reduce the risk of SIDS.

Risk Factors

No single factor means a baby is at greater risk of SIDS. A combination of different risk factors may play a role, including:

• Use of drugs, drinking, or smoking during pregnancy
• Male babies
• Prematurity or a low birth weight
• Poor prenatal care
• A family history of SIDS
• A mother younger than 20 years old
• Infant exposure to tobacco smoke
• Overheating

Most cases of SIDS occur between 2 and 4 months, and more than 90% of SIDS deaths occur in infants who are 6 months of age or younger. SIDS is less common after a baby reaches 8 months of age. However, parents should continue to follow safe sleep practices until the baby’s first birthday.

How to Prevent SIDS

SIDS typically doesn’t have warning signs or symptoms. That’s why creating a safe sleeping environment for all babies is important to prevent SIDS. Experts recommend the following:

Put Babies to Sleep on Their Backs: Infants who sleep on their back are at less risk of SIDS than babies who sleep on their stomach or on their side.

If your baby falls asleep in the car, a baby carrier, or a stroller, move your baby to a sleep surface on their back as soon as you can.

If your baby can roll from back to stomach and stomach to back, you do not need to move your baby onto their back. Make sure there are no items surrounding the baby that they could roll into and block airflow.

Use a Firm Sleep Surface: Cribs, bassinets, and portable cribs must meet the safety standards set out by the Consumer Product Safety Commission. A firm mattress that is tight-fitting, as well as a fitted sheet designed for the specific product, is recommended.

A firm surface is considered hard and should not indent when a baby is lying on it. Nothing else but the baby should be in the crib.

Don’t Share a Bed With Your Baby: The American Academy of Pediatrics (AAP) does not recommend bed sharing for any baby.

You should only bring your baby into your own bed to feed or comfort them. The baby should be placed on their back in their own bed when you are ready for sleep.

If there is a chance you will fall asleep with the baby in your bed, ensure there are no pillows, blankets, or other things that could cover the baby’s head or overheat your baby.

Share a Room With Your Baby: For at least the first six months, and ideally for the first year, the AAP recommends that the baby sleep in the same room as the parents. Place the crib or bassinet close to your bed. This can decrease the risk of SIDS by up to 50%.

Keep Objects Out of the Baby’s Crib: Loose bedding, soft objects, or any item that could increase the risk of suffocation, strangulation, or entrapment should be kept away from where the baby sleeps. This includes:

If you’re concerned your baby will be cold, you can dress them in sleep clothing.

Don’t Leave Your Baby on Furniture or Pillows: The Consumer Product Safety Commission states that more than two dozen infants died between 2012 and 2018 from being left on or near nursing pillows or pillow-like lounging pads.

Babies should never be left to sleep on couches, sofas, or armchairs. This is dangerous for the baby.

Use Pacifiers at Naps and Bedtime: Using a pacifier during naps and bedtime can help reduce the chance of SIDS, even if it falls out when the baby is sleeping.

If breastfeeding, wait until it’s going smoothly before trying a pacifier. Those not breastfeeding can offer a pacifier straight away. If a pacifier falls out during sleep, you don’t have to replace it.

Summary

Sudden infant death syndrome is the unexpected death of a baby who seemed to be healthy. The cause is still unknown, but research suggests that it involves brain abnormalities that put an infant at risk in certain sleep environments.

To help prevent SIDS, experts recommend putting babies on their back to sleep. They should also sleep in a crib or bassinet with a firm mattress. Keep soft toys or loose bedding out of the baby’s crib to avoid the risk of suffocation.