| Risk Factors
Sudden infant death syndrome (SIDS) refers to the unexpected, unexplained death of a child less than one year old. SIDS is rare during the first month of life. It peaks at 2-4 months of age, then gradually decreases.
Experts do not know the exact cause of SIDS. Many theories exist. Potential causes include:
- Abnormalities in a section of the brain that controls breathing during sleep and waking
- Abnormalities in the control of heart rhythm
- Changes in how serotonin, a neurotransmitter, functions in the brain
- Changes in some components of the immune system
- Inadequate arousal response to breathing obstruction or asphyxia—a lack of oxygen or excess carbon dioxide in the body caused by interruption of breathing; may cause unconsciousness
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SIDS is more common in infants less than 6 months old. Other factors that increase your infant's chance of SIDS include:
- Low birth weight
- Delayed fetal growth
- History of SIDS death in a sibling
- History of an acute life-threatening event
- Previous incident of unexplained severe apnea—when breathing is repeatedly interrupted and requires resuscitation
- Sleeping on the stomach or side rather than back
Other risk factors are more general and include:
during pregnancy or in a house where the baby is sleeping
, excessive caffeine, opiate, or
use during pregnancy
- Mother's age—younger than 20 during first pregnancy
- Black, Native American, and Alaskan Native families
- Sex: male
urinary tract infection
- No or late prenatal care
- Premature birth
- Recent infection and/or fever
- Cold weather in late fall or winter
- Low socioeconomic status or low level of education
- Co-sleeping in parents room
- Loose covers and blankets
A baby that dies of SIDS typically appears healthy. The baby may have had a
or gastrointestinal infection in the 2 weeks prior to death. There usually are no warning signs that a baby is about to have SIDS.
All possible illnesses and causes of death must be ruled out before a diagnosis of SIDS is made. A complete investigation will take place including:
- Assessment of the death scene
- Review of the baby and family's medical histories
Emergency medical personnel should be called as soon as the infant is discovered not breathing.
should be started right away. Seek medical care right away even if the baby starts breathing again. The cause of the incident should be fully evaluated. Families may need grief counseling after the death. Some parents find
There is no way to predict which infants will die of SIDS. Several actions may help you lower your child's chance of SIDS:
Last reviewed January 2015 by Kari Kassir, MD
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