Newborns who sleep on the backs (the supine position) in hospital nurseries seldom,if ever,spit up and when they do, it does not lead to any significant complications,new research indicates.While the "back to sleep" position is recommended to reduce the risk of sudden infant death syndrome,some hospital staff may be reluctant to place newborns on their backs while sleeping out of fear of aspiration,note researchers.But no study has examined how often spitting up occurs in the back sleeping position and whether it has serious consequences,according to May Anne Tablizo of the Children's Hospital Central California in Madera.