Effect of holding on co-regulation in preterm infants: a randomized controlled trial.
OBJECTIVE
To determine whether kangaroo holding of healthy preterm infants over the first eight weeks of an infant's life facilitates co-regulation of salivary cortisol between mother and infant.


METHODS
Randomized control trial. Infants were assigned to receive 1h of daily kangaroo (skin-to-skin contact on the chest of mother) or blanket holding (dressed and held in mother's arms). A registered nurse visited mothers weekly for eight weeks to encourage holding and provide information about infant development. A control group had no holding restrictions and received weekly brief social visits.


METHODS
The study included 79 preterm infants, born between 32 and 35weeks gestational age and were a mean of 15days (±5.7) at enrollment.


METHODS
Co-regulation was conceptualized as progressive reduction in the absolute difference between mother and infant cortisol levels across 60min of holding at each holding session. Mother and infant cortisol levels were measured before holding and at 30 and 60min after holding began during three holding sessions (baseline and at two and eight weeks after study initiation). Primary analyses were conducted using hierarchical linear models.


RESULTS
There was much variability in cortisol levels. Levels of mother and infant cortisol decreased during holding. No significant co-regulation occurred in any group at any holding session or over time.


CONCLUSIONS
Decreasing level of cortisol in both mothers and infants suggests that holding promoted the expected decline in stress hormone levels. However, supported holding methods did not differentially affect co-regulation compared to controls. Holding is pleasurable and stress may need to be present in order for mothers and infants to demonstrate co-regulation in cortisol levels.
University of Colorado Anschutz Medical Campus, College of Nursing, 13120 E. 19th Ave, C-288, Aurora, CO 80045, United States. Electronic address: madalynn.neu@ucdenver.edu.
Madalynn
M
Neu
University of Colorado School of Medicine, Department of Psychiatry, United States. Electronic address: nick.hazel@ucdenver.edu.
Nicholas A
NA
Hazel
Early Childhood Education and Early Intervention, University of Connecticut, United States. Electronic address: JoAnn.Robinson@UConn.edu.
Joann
J
Robinson
University of Colorado, Department of Biostatistics and Informatics, United States. Electronic address: Sarah.Schmiege@ucdenver.edu.
Sarah J
SJ
Schmiege
University of Colorado Anschutz Medical Campus, School of Medicine, Department of Psychiatry, United States. Electronic address: Mark.Laudenslager@ucdenver.edu.
Mark
M
Laudenslager
D000328:Adult; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D060127:Kangaroo-Mother Care Method; D008297:Male; D012463:Saliva / Q000737:chemistry
D006854:Hydrocortisone
Cortisol; Kangaroo holding; Mother–infant; Skin-to-skin