The role of NNS on GER, however, has not been yet clarified. It has been previously shown that the swallowing enhances the occurrence of lower oesophageal sphincter relaxations, which are known to represent a trigger stimulus for reflux episodes. On the other hand, the act of swallowing appears to promote the esophageal clearance of refluxate; hence, a possible influence of NNS on GER might be hypothesized. In a pH-metric study, performed by Orenstein et al. on infants younger than 6 months, NNS seemed to have a worsening effect on GER when applied in the prone posture, whereas in the seated position was associated with an ameliorative outcome; this controversial result, however, cannot be extended to the preterm population. To date, the efficacy of NNS by means of a pacifier on preterm infants symptomatic for GER has been preliminary evaluated only by Zhao et al., reporting an improvement of overall GER features (number of refluxes, reflux index, total time at pH<4) and a faster time of gastric emptying in the NNS group. However, this study was performed by pH monitoring, so that the effect of NNS on non-acid GER has not been evaluated yet.