Prematurity and neonatal noxious events exert lasting effects on infant pain behaviour

• Published in: Early human development Vol. 84; no. 6; pp. 351 - 355
• Main Authors: Abdulkader, Huda M., Freer, Yvonne, Garry, Emer M., Fleetwood-Walker, Susan M., McIntosh, Neil
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier Ireland Ltd 01.06.2008; New York,NY Elsevier; Amsterdam
• Subjects: Advanced Basic Science; Biological and medical sciences; Cross-Sectional Studies; Embryology: invertebrates and vertebrates. Teratology; Flexion withdrawal response; Fundamental and applied biological sciences. Psychology; Heel - injuries; Heel prick; Human infant; Humans; Infant; Infant Behavior; Infant, Newborn; Infant, Premature - psychology; Longitudinal Studies; Neonatal and Perinatal Medicine; Pain; Pain - etiology; Pain - psychology; Pain Measurement; Pain Threshold; Physical Stimulation - adverse effects; Sensitisation; Stress, Psychological - psychology; Term Birth - psychology; Von Frey filaments; Flexion withdrawal response; Heel prick; Pain; Human infant; Von Frey filaments; Sensitisation; Human; Neonatal; Prematurity; Infant; Behavior
• ISSN: 0378-3782; 1872-6232
• DOI: 10.1016/j.earlhumdev.2007.09.018

There is concern that exposure of preterm infants to noxious insults over a prolonged period may have long term effects on their developing nervous system. To investigate medium and long term effects of heel pricks in infants over the first year of life. Study 1—a longitudinal study, 2 days and 4 weeks after heel prick. Study 2—a cross sectional study over the first year of life. Study 1—13 healthy preterm (PT) infants. Study 2—63 full term (FT) and 62 PT infants, divided into 3 timed groups (0–20, 21–37 and 38–52 weeks postterm and corrected for prematurity). Threshold responses (flexion withdrawal (FWR) , gross body movements (GBM) and grimace (G)) to increasing mechanical force applied with Von Frey filaments. Study 1—Thresholds were all significantly lower (more sensitive) from the pricked heel compared to the contralateral side at 2 days and 4 weeks. Study 2—There were significant differences in threshold between PT and FT infants at all time points for both FWR ( P = 0.001, < 0.001, < 0.001) and GBM ( P = < 0.001, < 0.001, 0.009 respectively), the preterm infants always being lower. The threshold for the FWR in FT infants steadily increased, but the threshold for the PT infants remained the same. GBM thresholds increased during the year in both FT and PT infants, but were always significantly lower in the ex-preterm group ( P < 0.012). Either PT birth or repetitive procedures associated with such birth alters the sensitivity threshold of PT infants compared with FT infants for at least the first year of life.