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 to 4 months of age, then gradually decreases.

Experts do not know why some infants suddenly die. Research hopes to find a preventable cause. Many theories exist. It is likely that research will reveal that among babies who die of

SIDS there are several different, but important causes. Some suggested 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)

Factor is something that increase the chance of SIDS include:

• Infant's age: less than 6 months old
• Low birth weight
• Fetal growth retardation
• 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) requiring resuscitation
• Sleeping on the stomach or side rather than back
• Other risk factors are more general and include:
  • Mother's age: younger than 20 during first pregnancy
  • Poverty may play a role
  • Black, Native American, and Alaskan Native families
  • Sex: male
  • Smoking during pregnancy or in a house where the baby is sleeping
  • Alcohol , opiate, or cocaine use during pregnancy
  • History of anemia or a urinary tract infection while pregnant
  • No or late prenatal care
  • Premature birth
  • Recent infection and/or fever
  • Cold weather in late fall or winter
  • Overheating
  • Low socioeconomic status or low level of education
  • No pacifier use at bed time

A baby that dies of SIDS typically appears healthy. He or she may have had a cold or gastrointestinal infection in the two weeks prior to death. There usually are no warning signs that a baby is about to die of 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:

• Autopsy
• Assessment of the death scene
• Review of the baby's and family's medical histories

Emergency medical personnel should be called as soon as the infant is discovered not breathing. Infant CPR should be started immediately. Seek immediate medical care 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 support groups helpful.