Multimodal assessments of preterm temperament across the first year of life: Continuity, stability, and moderation by country of origin and infant age.

There is limited research regarding the continuity, stability, and role of country of origin in preterm infant temperament across the first year of life. This prospective longitudinal study examined patterns of mean-level continuity and individual-differences stability of select scales of temperament at 6 and 12 months in preterm infants from three countries, Chile (n = 47), United Kingdom (n = 44), and United States (n = 50). Temperament was assessed with the Infant Behavior Questionnaire and observed using the Bayley Behavior Rating Scale. Continuity and stability across infant age, country effects, and interactions of country and age on preterm infant temperament were examined. Chilean mothers rated infants higher in soothability, duration of orienting, and orientation/engagement compared with mothers from the United Kingdom and/or United States. Continuity of temperament from 6 to 12 months varied by country: Chilean mothers reported increasing smiling and laughter and activity level from 6 to 12 months, and mothers from the United Kingdom reported decreasing smiling and laughter and increasing fear from 6 to 12 months. Infant temperament was stable in all three countries. Correlations evidenced low concordance between maternal reports and examiner observations of infant temperament at 12 months. However, among Chilean infants, higher maternal reported activity level was associated with higher examiner observed orientation/engagement score.