This study aimed to identify the relationship between selected trace elements in human milk and depression, breastfeeding self-efficacy, sleep satisfaction, and the demographic and obstetric characteristics of lactating mothers. Forty lactating mothers recovering after birth in two postpartum care centers located in Changwon, South Korea, were studied. Calcium, sodium, iron, and selenium concentrations in human milk were analyzed using inductively coupled plasma mass spectrometry at the analysis center of Kyungnam University. Data were analyzed using descriptive statistics, the Kruskal-Wallis test, the Mann-Whiney U test, and Spearman's correlation coefficients using an SPSS 23.0 program. There were no significant differences in concentration of selected trace elements (calcium, sodium, iron, and selenium) in human milk according to demographic and obstetric characteristics. Sodium concentration was negatively correlated with breastfeeding self-efficacy (r = -0.51, CI = -0.71 to -0.24). Selenium concentration was negatively correlated with calcium concentration (r = -0.34, CI = -0.58 to 0.38). Postpartum depression was negatively correlated with sleep satisfaction (r = -0.46, CI = -0.67 to -0.17) and with breastfeeding self-efficacy (r = -0.41, CI = -0.64 to -0.11). Breastfeeding self-efficacy was positively correlated with sleep satisfaction (r = 0.48, CI = 0.20 to 0.69). This study suggests that sodium concentration in human milk is associated with breastfeeding self-efficacy.
Keywords: calcium; human milk; iron; postpartum; selenium; sodium.