The effect of kangaroo care on modulate chronic stress response in preterm infants and mothers

To assess stress experienced during Neonatal Intensive Care Unit (NICU) stay, we analyzed fingernail Cortisol (CORT) and Dehydroepiandrosterone (DHEA) levels and ratios in mothers and preterm infants (PI); compared hormones levels/ratio (CORT and DHEA) in kangaroo care (KC) versus standard care (SC) groups and examined relationships between PI hormone levels total days spent in the NICU. Mothers and their infants were recruited in the NICU, included levels I-IV and kangaroo care unit, within one week of infant birth in hospitals in Brazil. At 3 months after birth, mothers provided 3-month growth clippings from all ten digits of their own and their infants' fingernails. CORT and DHEA were measured using enzyme immunoassays (mothers) and high-performance-liquid-chromatography-with-mass-spectrometry (infants). Sample: n = 59 mothers (KC = 30/SC = 29) and 63 infants (KC = 32/SC = 31). Data were analyzed using non-parametric/parametric comparative statistics. NICU stay ranged from 3-103 days. For mothers in Kangaroo and Standard Care the CORT, DHEA levels and DHEA:CORT ratio (DC) ratio did not differ. Infants in KC had higher DHEA (p = 0.003) and a higher DC ratio (p = 0.011) than SC infants. Even though KC infants stayed in the NICU for a greater number of days than infants in SC, they had higher mean level of DHEA, and DC ratio, suggesting that KC played a role in promoting their stress regulatory capacities and may mitigate toxic effects of chronic hypercortisolemia. However, for mothers, KC did not reduce chronic stress compared to that in women in the SC condition. Further research warranted.