A Randomised Controlled Trial to Investigate the Autonomic Regulation of Mother's Presence on Their Infants

Purpose: To explore whether the presence of the mother provides a measurable, physiological regulatory function in infants younger than six months undergoing and recovering from clinical procedures.

Hospital care of ill infants has conventionally involved periods of maternal–infant separation especially in preparation for or recovery from clinical procedures. Extensive research in preterm and term infants exists that demonstrates the adverse effects of maternal separation. Better physiological outcomes and regulatory stability of infants have been measured during care provided with infants in skin-to-skin care  compared with the same care provided in closed servo-controlled incubators. There is good evidence indicating that the presence of the mother modulates the infant’s immature autonomic system in the neonatal period. This regulatory function has not yet been measured in older infants in clinical care settings.

 Methods: A prospective, single blinded, randomized controlled clinical trial was designed utilising a sample of 30 infants younger than 6-months who were undergoing surgery for inguinal hernia repair. Sample power was calculated and electronic randomisation applied. Institutional research ethics board approval was granted. Subjects were recruited and randomized prior to surgery and all mothers consented to standard of care.  In the research facility this meant that an infant was placed on a stretcher and accompanied into the operating theatre by a nurse and a porter. The infant, similarly accompanied, was returned to the mother after recovery room care.  Mothers of infants randomised to the intervention group were invited to accompany their infants into surgery and recovery.    Data included continuous monitoring of Heart Rate Variability (HRV) as core data as HRV is a validated measure of autonomic nervous system activity.  Impedance-cardiography, continuous observation and postoperative pain scores, validated with the mother, were added to the data set

Results: Data was blinded during analysis. Results indicated a statistically significant increase in autonomic activity with sympathetic activation in infants without their mothers. These objectively verifiable physiological indicators of stress did not always correlate with infant behaviour.

Conclusion: While infant separation from a mother is well recognised as being stressful, previous evidence relied on observational and subjective data. In this study, objective physiological stress were present while babies seemed to be ‘settled’, indicating that observational and infant behavioural data may be insufficient a measure autonomic excitation or stress.  Increased heart rate variability is a good objective indicator of stress and many modern vital signs monitors already have the capacity to calculate HRV.

This study is the first to measure the infants’ physiological responses to maternal separation during and after a clinical intervention in this age group of infants. It is imperative that these outcomes be communicated in appropriate ways to mothers, families and clinical personnel. Physiological stability has been the core responsibility of nurses and other clinicians, shifting practice to utilise the emerging evidence of the mother’s presence will prove an interesting challenge.