The estimate of the percentage of SIDS deaths that are actually infanticide varies from less than 1% to up to 5% of cases.Some have underestimated the risk of two SIDS deaths occurring in the same family; the Royal Statistical Society issued a media release refuting expert testimony in one UK case, in which the conviction was subsequently overturned. Prevention
A number of measures have been found to be effective in preventing SIDS, including changing the sleeping position to supine, breastfeeding, limiting soft bedding, immunizing the infant and using pacifiers. The use of electronic monitors has not been found to be useful as a preventative strategy. The effect that fans might have on the risk of SIDS has not been studied well enough to make any recommendation about them. Evidence regarding swaddling is unclear regarding SIDS. A 2016 review found tentative evidence that swaddling increases the risk of SIDS, especially among babies placed on their bellies or sides while sleeping.Measures not shown to be useful include positioning devices and baby monitors. In the United States, companies that sell the monitors do not have FDA approval for them as medical devices. Sleep positioning
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.
Although studies have identified risk factors for SIDS, such as putting infants to bed on their bellies, there has been little understanding of the syndromes biological process or its potential causes. Deaths from SIDS are unlikely to be due to a single cause, but rather to multiple risk factors. The frequency of SIDS does appear to be influenced by social, economic, or cultural factors, such as maternal education, race or ethnicity, or poverty. SIDS is believed to occur when an infant with an underlying biological vulnerability, who is at a critical development age, is exposed to an external trigger. The following risk factors generally contribute either to the underlying biological vulnerability or represent an external trigger:

Tobacco smoke
SIDS rates are higher in babies of mothers who smoke during pregnancy. Between no smoking and smoking one cigarette a day, on average, the risk doubles. About 22% of SIDS in the United States is related to maternal smoking. SIDS correlates with levels of nicotine and its derivatives in the baby. Nicotine and derivatives cause alterations in neurodevelopment. Sleeping
Placing an infant to sleep while lying on the belly or side rather than on the back increases the risk for SIDS. This increased risk is greatest at two to three months of age. Elevated or reduced room temperature also increases the risk, as does excessive bedding, clothing, soft sleep surfaces, and stuffed animals in the bed. Bumper pads may increase the risk of SIDS due to the risk of suffocation.