Longitudinal assessment of pituitary-thyroid axis and adrenal function in preterm infants raised by 'kangaroo mother care'

Objective: To assess whether complete kangaroo mother care (KMC), a skin-to-skin contact intervention, would affect longitudinal/developmental patterns of hormonal change. Method: An open randomized controlled trial was conducted in a large tertiary care hospital, comparing KMC and traditional care for newborn infants weighing less than 2,001 g. Eighty-seven healthy preterm (<37 weeks gestational age) infants from this study provided three blood-spot samples on filter paper: at randomization (postnatal age 1-5 days), 2 weeks later, and at calculated term (41 weeks gestational age). They met a number of additional inclusion criteria including discharge from the hospital within the first postnatal week. The levels of 17α-hydroxy-progesterone (17-OHP), thyroxine- stimulating hormone (TSH) and thyroxine (T₄) were assessed by radioimmunoassay. Birth weight (<1,800 or ≥1,800 g) and prenatal maternal corticosteroid treatment were taken into account in the analysis. Interventions: Complete KMC includes early discharge, positioning the infant on the parent's chest in an upright position, 24 h/day in skin-to-skin contact, and breast-feeding. In the traditional care group, infants were discharged according to routine hospital practice. Results: Levels of 17-OHP and TSH decreased significantly from eligibility to calculated term while T₄ levels did not change significantly over time. Most importantly, overall, treatment (KMC) did not interact with the pattern of physiological change. Conclusions: Maturation of the pituitary-thyroid axis and adrenal function is apparently not compromised by KMC, at least in healthy preterm infants.