This research is being done to understand better how a mother's emotional well-being and lifestyle, such as her levels of stress, fatigue, depression, anxiety, sleep quality, and eating habits, might affect the levels of melatonin and sIgA in her breast milk.

This study aims to learn more about promoting mothers' and babies' health by studying various maternal factors. Gaining a better understanding of the connections between a mother's emotional and physical state and the quality of her breast milk could lead to new recommendations and support strategies to improve the mother's well-being.

Participants will be involved in the study during the immediate postpartum period. They will be asked to provide a 5mL sample of breast milk on day 14 postpartum between 6am and 9am. Participants will be asked to use an orange ambient light during nighttime infant care from the time they come home from the hospital up until the time of breastmilk collection to avoid harsh lighting while providing care for their baby, which may affect melatonin levels.

In addition to breast milk collection, participants will complete a series of questionnaires related to their emotion well-being and lifestyle. These questionnaires will help the research team understand how factors like stress, fatigue, depression, anxiety, sleep, and dietary patterns may be associated with melatonin and sIgA levels in breast milk. Information regarding medications and gestational age of the newborn will be collected from medical records to further assist in data analysis.

Inclusion criteria:

• Possess a refrigerator with a freezer or a standalone freezer for sample storage at home.
• Ability to be contacted by telephone.
• Having internet access at home.
• Being in the immediate (0-14 days) postpartum period.
• Currently breastfeeding or planning to breastfeed, regardless of the type.

Exclusion criteria:

• Newborns with congenital malformations.
• Newborns with birth weights less than 2,500g or greater than 4,000g.
• Gestational age less than 37 completed weeks or greater than 42 completed weeks.
• Mothers hospitalized in an intensive care unit (ICU).
• Newborns hospitalized in the neonatal intensive care unit (NICU) or special care nursery (SCN).
• Mothers using sleep aids (e.g., Benadryl, Unisom, Melatonin, Valerian).
• Mothers currently being treated for pharmacologically treated mood and sleep disorders.
• Mothers with acute infections longer than 7 days postpartum. Mothers will be withdrawn from study if antibiotics are taken between 7 and 14 days postpartum.

New mothers receiving care at Mayo Clinic Health System in Eau Claire, Wisconsin.