Internalizing behaviours in school-age children born very preterm are predicted by neonatal pain and morphine exposure.

BACKGROUND

Greater neonatal pain is associated with higher internalizing behaviours in very preterm infants at 18 months corrected age, but it is unknown whether this relationship persists to school age. Moreover, it is unclear whether morphine ameliorates or exacerbates the potential influence of neonatal pain/stress on internalizing behaviours. We examined whether neonatal pain-related stress is associated with internalizing behaviours at age 7 years in children born very preterm, and whether morphine affects this relationship.

METHODS

One hundred one children born very preterm (≤32 weeks gestation) were seen at mean age 7.7 years. A parent completed the Parenting Stress Index and Child Behavior Checklist questionnaires. Neonatal pain-related stress (the number of skin-breaking procedures adjusted for clinical factors associated with prematurity) was examined in relation to internalizing behaviour, separately in subjects mechanically ventilated and exposed to both pain and morphine (n = 57) and those never mechanically ventilated, exposed to pain but not morphine (n = 44).

RESULTS

In the non-ventilated group, higher skin-breaking procedures (p = 0.037) and parenting stress (p = 0.004) were related to greater internalizing behaviours. In the ventilated group, greater morphine exposure (p = 0.004) was associated with higher child internalizing scores.

CONCLUSIONS

In very preterm children who undergo mechanical ventilation, judicious use of morphine is important, since morphine may mitigate the negative effects of neonatal pain on nociception but adversely affect internalizing behaviours at school age. Management of procedural pain needs to be addressed in very preterm infants in the neonatal intensive care unit, to prevent long-term effects on child behaviour.