SIDS is the sudden death of infants who are 1 month to 1 year old. There is no explanation of what causes the deaths. Also, there are no specific symptoms to indicate the condition. SIDS is diagnosed only when all other possible causes of death have been ruled out by a detailed evaluation of the medical history.

New research shows that there could be ways to decrease the risks of SIDS.
Parents often place their babies in their own beds as bed shearing is thought to bring closeness and make breastfeeding easier. Other reason for sleeping together is inability to afford separate beds for the babies.
However, it is advised that babies should be placed in their own cribs to sleep and not in the parents’ beds. Babies who sleep in an adult bed face a 40 % more risk of suffocation than the babies who sleep in standard cribs. Also, infants should not share beds with their siblings, or sleep with adults on a couch or armchair either.
Baby’s crib should be placed in the parent’s room to make the breastfeeding easier.
Further more, babies should sleep on their backs on a firm crib mattress, covered by a sheet. Soft and cushy beds should be avoided. Giving pacifiers at naptime and bedtime are also associated with a reduced risk of SIDS.

The last but not least warning is smoking during pregnancy which increases a baby's risk of SIDS.