Maternal Speech Decreases Pain Scores and Increases Oxytocin Levels in Preterm Infants During Painful Procedures

Overview

Preterm infants undergo early separation from parents and are exposed to frequent painful clinical procedures, with resultant short- and long-term effects on their neurodevelopment. We aimed to establish whether the mother's voice could provide an effective and safe analgesia for preterm infants and whether endogenous oxytocin (OXT) could be linked to pain modulation. Twenty preterm infants were exposed to three conditions-mother's live voice (speaking or singing) and standard care-in random order during a painful procedure. OXT levels (pg/mL) in saliva and plasma cortisol levels were quantified, and the Premature Infant Pain Profile (PIPP) was blindly coded by trained psychologists.

Preterm birth rates are continuously increasing in almost all countries, with 15 million premature infants being born every year worldwide1. Despite rapid advances in technology, the number of preterm-born children who show short- and long-term sequelae of prematurity, even before reaching school age, remains high. Around 40% of low birth weight preterm infants experience a complex spectrum of unfavourable neurodevelopmental outcomes when compared with their pairs at term. Thus, prematurity is of great concern for health policies in both low- and high-income countries. The impaired development of preterm infants is not only associated with medical factors, but it is also at least partly a consequence of the atypical early-life environment of these infants, including exposure to pain and separation from the primary caregivers. The aim of the present work was first, to assess whether early closeness with parents during essential but painful clinical procedures could have a positive role in pain modulation in preterm infants, thus contributing to the universal right to pain relief. Second, we aimed to investigate the possible role of the oxytocinergic system in this putative pain modulation through maternal vocal contact. In the present protocol, we introduce the effects of separation and early pain exposure as two environmental factors that are even more deleterious when concomitant, inducing short- and long-term problems in the preterm infant's development. We then suggest that there are protective effects of early closeness between parents and preterm infants in early care and, more specifically, of early vocal contact between parents and preterm infants during hospitalisation. Lastly, we discuss the role of oxytocin (OXT) as a crucial biomarker for attachment processes and in relation to brain inflammation due to stressful procedures for preterm infants in the neonatal intensive care unit (NICU).