Development of esophageal peristalsis in preterm and term neonates.

High-resolution manometry demonstrates a chain of 3 sequential pressure segments that represent esophageal peristalsis in children and adults. We performed high-resolution manometry in preterm and term neonates to determine the ontogenesis of esophageal motility with regard to this segmental architecture.Sixteen preterm (gestational age 32.9 +/- 2.6 weeks at examination) and 14 term neonates (38.9 +/- 1.6 weeks) underwent manometry with a 9-lumen perfused catheter having recording side holes spaced at 1-cm intervals. Pressure responses to swallows were evaluated for the presence of peristaltic segments on isobaric contour maps by an investigator who was blinded to gestational age.The second segment was well developed in > or =50% of swallows in all preterm and term neonates. In contrast, the first segment was present in > or =50% of swallows in only 2 preterm neonates (12.5%) and 8 term neonates (57.1%; P < .05 for each compared with second segment) with identical findings for the third segment (12.5% preterm and 57.1% term neonates; P < .05 for each). Completed peristalses with intact segmental contraction sequences throughout the esophageal body were present in 26% +/- 6% of swallows in preterm neonates vs 55% +/- 9% in term neonates (P = .01).The second pressure segment in the midesophagus (proximal smooth-muscle region) is well developed before term. Presence of other segments significantly improves at term, but peristalsis remains incomplete in nearly half of swallows. Control mechanisms for both striated- and smooth-muscle esophageal regions are incompletely developed in neonates, the outcome of which could participate in infant reflux disease.