Babies sleep safest on their backs

One of the easiest ways to lower your baby's risk of SIDS (Sudden Infant Death Syndrome) is to put him or her on the back to sleep, for naps and at night. Health care providers used to think that babies should sleep on their stomachs, but research now shows that babies are less likely to die of SIDS when they sleep on their backs. Placing your baby on his or her back to sleep is the number one way to reduce the risk of SIDS.

Q. But won't my baby choke if he or she sleeps on his or her back?
A. No. Healthy babies automatically swallow or cough up fluids. There has been no increase in choking or other problems for babies who sleep on their backs.

source: http://www.nichd.nih.gov/publications/pubs/safe_sleep_gen.cfm