Impact of Vitamin D Supplements on Mental Health and Milk Composition in Mothers Living in Idaho

Mothers of preterm infants experience exaggerated emotional stressors compared to those typically associated with new motherhood, making these women particularly vulnerable to postpartum depression. As many as 70% of mothers of preterm infants experience postpartum depression compared to only 12.5% of those delivering full-term infants. Increased stress and depression during this critical period are detrimental because they hamper a mother's ability to care for her infant and are associated with increased neonatal sepsis and mortality, decreased neonatal growth, and delayed motor and cognitive development. Postpartum depression is also associated with excessive maternal weight gain and risk for metabolic diseases, anxiety, and sleep disturbances. Stress in breastfeeding mothers can also alter circulating concentrations of some bioactive components (e.g., immunoglobulins, cortisol) that can transfer into milk. As such, understanding factors predisposing these vulnerable women to extreme levels of stress and finding ways to lower this stress and lessen its negative health outcomes on mothers and infants are important public health challenges. The March of Dimes estimates that 8.5% of births in Idaho are preterm, making this topic particularly relevant for Idaho women. Risk factors for postpartum depression in mothers delivering term or preterm infants are complex, but maternal nutrient deficiencies may be involved. Vitamin D status, for instance, is inversely correlated with risk of postpartum depression in women delivering term infants. However, vitamin D interventions have yielded inconsistent results, perhaps due to confounding impacts of geographic location, skin color, and endogenous vitamin D synthesis. Endogenous vitamin D synthesis requires cutaneous sunlight exposure, placing Idaho women at even greater risk of vitamin D deficiency - particularly in the winter when days are extremely short (only 7 hr on the winter solstice). The impact of maternal vitamin D s