Preschool Needle Pain Responding: Establishing 'Normal'.

The current study sets forth to provide descriptive data for preschool vaccination pain responding as well as examine longitudinal relationships over early childhood. Growth mixture modeling was first used to describe stable subgroups of preschoolers on the basis of their pain response patterns over 2-minutes post-needle. Secondly, a parallel-process growth curve model was used to assess the stability of acute pain responding from 12 months of age to preschool age. Specifically, we examined whether preschool pain-related distress or regulation could be predicted from 12-month acute pain responding. Preschool participants were part of a Canadian longitudinal cohort (The Opportunities to Understand Childhood Hurt [OUCH] cohort; N = 302). Growth mixture modeling analyses discerned 3 distinct groups of preschoolers, with an important minority not regulating to low-no pain by 2 minutes post-needle. There were no significant associations between 12-month and preschool pain responding. These results highlight the steep trajectory of development between these different stages of early childhood and the variability of pain responding at the preschool vaccination. PERSPECTIVE: This study provides descriptive data for preschool vaccination pain responding as well as examines longitudinal relationships over early childhood. Demonstrating significantly different pain patterns from infancy, 25% of preschoolers are displaying suboptimal regulation trajectories. This considerable minority poses a significant concern because of the established trajectory of phobia onset in middle childhood.