Stress Responses of Neonates Related to Maternal Characteristics

PURPOSE: To investigate the pre- and post-heelstick stress response patterns of infants and to identify related maternal factors. MATERIALS AND METHODS: Fifty-two mothers and their 57 infants were studied. Stress response patterns in neonates were collected by measurements of pulse rate, oxygen saturation, and salivary cortisol. Maternal demographic factors and awakening saliva were collected. RESULTS: Median level of pulse rate of infant increased from 132.1 to 140.4 beats per minute and salivary cortisol was elevated from 0.41 µg/dL to 0.70 µg/dL during the periods of discomfort, while oxygen saturation decreased from 97% to 95%. Infant's pulse rate change was negatively correlated with gestational age (GA) (r = - 0.37, p < 0.05), whereas the change of infants' salivary cortisol was correlated positively with maternal age (r = 0.29, p < 0.05). GA was the only independently significant predictor of pulse rate responses (R(2) = 0.15, p < 0.05). Influence of maternal age on infants' salivary cortisol changes (R(2) = 0.09, p < 0.05) was observed in a stepwise multiple regression. CONCLUSION: These findings suggest that maternal age and gestational period can be influential factors for stress responses in infants. Therefore, it would be important to consider the demographic characteristics of mother-infant pairs to evaluate these influential factors.