Sudden infant death syndrome (SIDS), also known as cot death or crib death, is the sudden unexplained death of a child less than one year of age. Diagnosis requires that the death remains unexplained even after a thorough autopsy and detailed death scene investigation. SIDS usually occurs during sleep. Typically death occurs between the hours of 00:00 and 09:00. There is usually no evidence of struggle and no noise produced.
There are no symptoms. Babies who die of SIDS do not appear to suffer or struggle.
The exact cause of SIDS is unknown. The requirement of a combination of factors including a specific underlying susceptibility, a specific time in development, and an environmental stressor has been proposed. These environmental stressors may include sleeping on the stomach or side, overheating, and exposure to cigarette smoke. Accidental suffocation such as during bed sharing may also play a role. Another risk factor is being born before 39 weeks of gestation. SIDS make up about 80% of sudden and unexpected infant deaths (SUIDs), with other causes including infections, genetic disorders, and heart problems. While child abuse in the form of intentional suffocation may be misdiagnosed as SIDS, this is believed to make up less than 5% of cases.
A number of measures have been found to be effective in preventing SIDS including changing the sleeping position, breastfeeding, limiting soft bedding, immunizing the infant and using pacifiers. The use of electronic monitors has not been found to be useful and is thus not recommended. Evidence regarding fans and swaddling is unclear.
Sleeping on the back has been found to reduce the risk of SIDS. It is thus recommended by the American Academy of Pediatrics and promoted as a best practice by the US National Institute of Child Health and Human Development (NICHD) "Safe to Sleep" campaign. The incidence of SIDS has fallen in a number of countries in which this recommendation has been widely adopted. Sleeping on the back does not appear to increase the risk of choking even in those with gastroesophageal reflux disease. While infants in this position may sleep more lightly this is not harmful. Sharing the same room as one's parents but in a different bed may decrease the risk by half.
The use of pacifiers appears to decrease the risk of SIDS although the reason is unclear. The American Academy of Pediatrics considers pacifier use to prevent SIDS to be reasonable. Pacifiers do not appear to affect breastfeeding in the first four months, even though this is a common misconception.
Product safety experts advise against using pillows, overly soft mattresses, sleep positioners, bumper pads, stuffed animals, or fluffy bedding in the crib and recommend instead dressing the child warmly and keeping the crib "naked."
Blankets should not be placed over an infant's head. It has been recommended that infants should be covered only up to their chest with their arms exposed. This reduces the chance of the infant shifting the blanket over his or her head.
In colder environments where bedding is required to maintain a baby's body temperature, the use of a "baby sleep bag" or "sleep sack" is becoming more popular. This is a soft bag with holes for the baby's arms and head. A zipper allows the bag to be closed around the baby. A study published in the European Journal of Pediatrics in August 1998 has shown the protective effects of a sleep sack as reducing the incidence of turning from back to front during sleep, reinforcing putting a baby to sleep on its back for placement into the sleep sack and preventing bedding from coming up over the face which leads to increased temperature and carbon dioxide rebreathing. They conclude in their study, "The use of a sleeping-sack should be particularly promoted for infants with a low birth weight." The American Academy of Pediatrics also recommends them as a type of bedding that warms the baby without covering its head.
A large investigation into diphtheria-tetanus-pertussis vaccination and potential SIDS association by Berlin School of Public Health, Charité – Universitätsmedizin Berlin concluded: "Increased DTP immunisation coverage is associated with decreased SIDS mortality. Current recommendations on timely DTP immunisation should be emphasised to prevent not only specific infectious diseases but also potentially SIDS."
Many other studies have also reached conclusions that vaccinations reduce the risk of SIDS. Studies generally show that SIDS risk is approximately halved by vaccinations.
SIDS is a diagnosis of exclusion and should be applied to only those cases in which an infant's death is sudden and unexpected, and remains unexplained after the performance of an adequate postmortem investigation, including:
- an autopsy (by an experienced pediatric pathologist, if possible);
- investigation of the death scene and circumstances of the death;
- exploration of the medical history of the infant and family.
After investigation, some of these infant deaths are found to be caused by accidental suffocation, hyperthermia or hypothermia, neglect or some other defined cause
Families who are impacted by SIDS should be offered emotional support and grief counseling. The experience and manifestation of grief at the loss of an infant are impacted by cultural and individual differences.