Maternal Circadian Disruption from Shift Work and the Impact on the Concentration of Melatonin in Breast Milk.

Melatonin in breast milk exhibits a 24-hour circadian rhythm, present in nighttime breast milk but nearly undetectable in daytime breast milk. Shift work can disrupt the circadian timing of individuals, evident in changes in melatonin in saliva and urine samples. However, it is unknown whether these changes are also reflected in breast milk from a shift working mother.

High-Temperature Pasteurization Used at Donor Breast Milk Banks Reduces Melatonin Levels in Breast Milk.

Donor human milk banks are used when breast milk directly from mothers is unavailable or insufficient. Breast milk contains melatonin, which exhibits a 24-hour pattern. Melatonin promotes sleep onset and is barely detected in daytime milk but rises in the evening and peaks early in the morning.