Final answer:
The most significant recommendation to prevent Sudden Infant Death Syndrome (SIDS) is to place infants on their back for sleep in a crib clear of suffocation hazards, avoid overheating, and maintain a smoke-free environment.
Step-by-step explanation:
To protect infants from Sudden Infant Death Syndrome (SIDS), the most important practice that nurses should instruct new parents to do is to place the infant on their back for sleep. Research has consistently shown that back-sleeping is the safest position for infants, minimizing the risk of SIDS. Moreover, it is advised that the crib should be free from items like blankets, pillows, or padded crib bumpers, which can pose suffocation hazards. Additionally, keeping the infant's head uncovered during sleep to prevent overheating and ensuring a smoke-free environment are crucial recommendations for reducing the risk of SIDS.
While checking on the infant frequently and following recommended immunization schedules are important practices, they are not as directly related to the prevention of SIDS as the sleep position and crib safety measures.