Kathy,

The American Academy of Pediatrics has two great pamphlets (one for parents,
the other for professionals) that explains the rationale for the strong
recommendation for the supine sleeping position.

In the US (as well as New Zealand and Australia), there has been a
significant reduction in Sudden Infant Death since more and more parents have
placed infants in the supine position.  Apparently the side lying position is
not as protective in reducing the risk of SIDS as supine position.  Also the
risk of aspiration is not increased by a supine sleeping position.  I know
this is counter intuitive!  Keep in mind we are addressing risk reduction
rather than elimination of SIDS.  Still possible for a infant to die of SIDS
in the supine position as there are many factors for SIDS.  Just as an infant
can aspirate in any position.

BTW infants with anatomical problems with their airway may need to NOT be
placed in the supine position during sleep.  The recommendation is for normal
infants.

Pierrette Mimi Poinsett MD FAAP
diplomate American Board of Pediatrics
and mom who puts her baby to sleep in supine position always