You may read some websites or hear individuals suggest that tummy sleeping is better for babies who suffer from reflux, however SIDS Australia recommend that the supine position or back sleeping is the best way to sleep your baby from birth to prevent the risk of SIDS, even for those babies that suffer from reflux.
This recommendation is supported by the recent research of Professor Heather Jeffery and her team from Royal Prince Alfred’s Department of Neonatal Medicine and theDepartment of Obstetrics and Gynecology at theUniversity of Sydney. They have reported that an infants’ airway protective response (swallowing & arousal) is compromised in the prone (tummy) sleeping position during active sleep, even in healthy infants exposed to minute pharyngeal fluid volumes of 0.4 ml. This is because the swallowing rate is reduced significantly, and there is no compensatory increase in arousal. The reduction in airway protective reflexes when in the prone (tummy) position and in active sleep may be the mechanism for the increased risk of SIDS in the prone position. (Jeffery et al 1999)
For more information see Baby care