<unk>  <unk> , also known as cot<unk>  or crib<unk> , is the<unk>  unexplained<unk>  of a child of less than one year of age. Diagnosis requires that the<unk>  remain unexplained even after a thorough autopsy and detailed<unk>  scene investigation.<unk>  usually occurs during sleep. Typically<unk>  occurs between the hours of midnight and 9:00 a.m. There is usually no noise or evidence of struggle.<unk>  remains the leading cause of<unk>  mortality in Western countries, contributing to half of all post-neonatal<unk> s. The exact cause of<unk>  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 tobacco smoke. Accidental suffocation from bed sharing (also known as co-sleeping) or soft objects may also play a role. Another risk factor is being born before 39 weeks of gestation.<unk>  makes up about 80% of<unk>  and unexpected<unk><unk> s (SUIDs). The other 20% of cases are often caused by infections, genetic disorders, and heart problems. While child abuse in the form of intentional suffocation may be misdiagnosed as<unk> , this is believed to make up less than 5% of cases. The most effective method of reducing the risk of<unk>  is putting a child less than one year old on their back to sleep. Other measures include a firm mattress separate from but close to caregivers, no loose bedding, a relatively cool sleeping environment, using a pacifier, and avoiding exposure to tobacco smoke. Breastfeeding and immunization may also be preventive. Measures not shown to be useful include positioning devices and baby monitors. Evidence is not sufficient for the use of fans. Grief support for families affected by<unk>  is important, as the<unk>  of the<unk>  is<unk> , without witnesses, and often associated with an investigation. Rates of<unk>  vary nearly tenfold in developed countries from one in a thousand to one in ten thousand. Globally, it resulted in about 19,200<unk> s in 2015, down from 22,000<unk> s in 1990.<unk>  was the third leading cause of<unk>  in children less than one year old in the United States in 2011. It is the most common cause of<unk>  between one month and one year of age. About 90% of cases happen before six months of age, with it being most frequent between two months and four months of age. It is more common in boys than girls. Rates of<unk>  have decreased in areas with "safe sleep" campaigns by up to 80%. Video explanation
Sudden infant death syndrome
Genetic disorder
Shaken baby syndrome
Infection
Blue baby syndrome
Child abuse
Neonatal meningitis
Infant respiratory distress syndrome