What is SIDS & SUID?

Sudden infant deaths are tragic and often preventable, and many occur when infants are sleeping. Each year, about 3,500 babies die during sleep in the U.S. because of unsafe sleep environments, according to the American Academy of Pediatrics (AAP). You may hear your health care provider use the terms “SUID” and “SIDS.”

SUID means “sudden unexpected infant death.” The National Institute of Child Health and Human Development (NICHD) explains that SUID is the “death of an infant younger than 1 year of age that occurs suddenly and unexpectedly.” 
SIDS means “sudden infant death syndrome.” For about half of all SUID cases, the cause of the infant’s death cannot be found, even after investigation. These deaths are classified as SIDS. 

The risk of sleep-related infant death can be reduced by following safe-sleep practices. Here are ways to reduce the risk for healthy babies up to 1 year of age:

  • Put your baby to sleep on her back every time. Though well-meaning family and friends may give other advice, always put your baby down on her back. Babies who sleep on their backs are at much lower risk than those who sleep on their tummies or sides, and this is true for naps and nighttime sleep. The SIDS rate is higher for African American babies for complex and little-understood reasons, including that they are less likely to be placed on their backs to sleep. (The AAP notes that a small number of infants with special medical conditions should be put to sleep on their stomachs—consult your doctor if your baby has a special condition.)
  • Keep soft items out of your baby’s sleep spaceDon't use pillows, blankets, quilts, or crib bumpers (which are banned as hazardous products). Keep toys such as stuffed animals out of your baby’s crib for at least the first year. 
  • Don’t smoke or allow anyone to smoke around your baby. Exposure to secondhand smoke increases babies’ risk of SIDS.
  • Avoid overbundling. Dress your baby in a one-piece sleeper or a wearable blanket to reduce the risk of overheating, which increases the risk of SIDS. And keep the room where your baby sleeps at a comfortable temperature (ideally, 68° to 72° F).
  • Consider running a fan in your baby’s room. Some studies have suggested that air movement in the sleep environment reduces the risk of SIDS.
  • Breastfeed. Studies show that breastfeeding reduces the risk of SIDS, with the greatest protection seen in babies who are exclusively breastfed. 
  • Offer a pacifier. The AAP notes that offering your baby a pacifier (not one attached to clothing or an object) at nap time and bedtime cuts the risk of SIDS. If the pacifier falls out of your baby's mouth during sleep, you don't need to put it back in.
  • Share your room. Sleep in the same room with your baby for at least the first 6 months or ideally, for their first year of life. Share your room but put your baby on a sleeping surface separate from yours.
  • Put your baby to sleep on a firm surface. The safest sleep surface is a mattress that fits tightly in a crib, covered with a fitted sheet. Never put your baby to sleep on a water bed, cushion, or sheepskin. Your sleep posture matters too: Don’t fall asleep with your baby while you’re on a sofa or in a chair, the AAP advises. It’s safest to feed your baby on your bed (with pillows and other items removed) than in a chair or sofa. If you do feed your baby on your bed and fall asleep, move him back to his own bed when you wake up. Lastly, never sleep with your baby if you have had alcohol, illegal substances, or other products that may make it hard for you to awaken from sleep.

Follow these guidelines to keep your baby safe during sleep. And for information on reducing risks in the home environment at other times, read this

Last updated March 16, 2023

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