Neuroendocrine and immune relationships in postpartum fatigue

To explore relationships between fatigue, depression, stress, and infection in the postpartum.

This was a cross-sectional, correlational design with a sample of 119 new mothers at 4 to 6 weeks postpartum. Mothers completed fatigue, mood, and stress instruments as well as maternal and infant infection checklists. Morning blood and hindmilk (in breastfeeders) samples were collected. ELISA was used to measure prolactin, cortisol, melatonin, and secretory IgA (sIgA). Correlations between psychosocial, health, and biologic variables were explored.

Fatigue was correlated with symptoms of infection in both mothers and babies, with perceived stress and postpartum stress as well as with depression. Serum prolactin was inversely associated with depression. Milk sIgA was related to milk prolactin and inversely related to stress. Milk melatonin and prolactin were inversely related, and fatigue scores were correlated with melatonin and inversely with prolactin.

The data suggest that fatigue, stress, depression, and infection are related in postpartum mothers and that these relationships extend to levels of serum hormones and milk factors. It is possible that a cycle is established that multiplies the effects of fatigue when mothers experience stress and that this cycle of stress and fatigue may lead to immune deficits and infectious illnesses.