SIDS is the leading cause of death in infants 1 month to 1 year old. According to the National Institute of Child Health and Human Development, you can reduce the risk for SIDS by always putting your baby down to sleep on his or her back; using a firm mattress in a crib clear of soft objects or toys; keeping the room temperature comfortable (not too hot); and offering your child a clean, dry pacifier when he or she lies down to sleep.