Symptoms and causes

A combination of physical and sleep environmental factors can make an infant more vulnerable to SIDS. These factors vary from child to child.

Although sudden infant death syndrome can strike any infant, researchers have identified several factors that might increase a baby's risk. They include:

  • Sex. Boys are slightly more likely to die of SIDS.
  • Age. Infants are most vulnerable between the second and fourth months of life.
  • Race. For reasons that aren't well-understood, nonwhite infants are more likely to develop SIDS.
  • Family history. Babies who've had siblings or cousins die of SIDS are at higher risk of SIDS.
  • Secondhand smoke. Babies who live with smokers have a higher risk of SIDS.
  • Being premature. Both being born early and having a low birth weight increase your baby's chances of SIDS.
July 12, 2017
  1. About SIDS and safe infant sleep. National Institute of Child Health and Human Development. Accessed Feb. 28, 2017.
  2. Corwin MJ. Sudden infant death syndrome. Accessed Feb. 28, 2017.
  3. Task Force on Sudden Infant Death Syndrome. SIDS and other sleep-related infant deaths: Updated 2016 recommendations for a safe infant sleeping environment. Pediatrics. 2016;138:e20162938.
  4. Sudden infant death syndrome (SIDS). American Lung Association. Accessed Feb. 28, 2017.

Sudden infant death syndrome (SIDS)