[Sudden unexpected death in infancy: Update and preventive measures].

Sudden unexpected death in infancy (SUDI) - defined as the death of a child under 1 year of age du ring sleep with no initially obvious cause - remains one of the most common causes of post-neonatal mortality. Approximately 3,500 infants die annually in the United States from sleep-related deaths. A complex and multifactorial origin is postulated in a vulnerable infant. However, the pathophysiology of SUDI has not been fully understood. Health care providers play a key role in promoting preventive measures described in the literature, which include sleeping in a supine position on a firm surface, avoiding smoking and co-sleeping, promoting breastfeeding, among others. The objective of this re view is to summarize the main epidemiological and physiopathological characteristics of SUDI, and safe sleep-related factors.