Psychological stress reduces the immunological benefits of breast milk

Stress Health. 2019 Dec;35(5):681-685. doi: 10.1002/smi.2903. Epub 2019 Nov 12.


Our study aimed to assess the impact of maternal psychological stress on the immunological components of breast milk. Eighty-nine women participated in the study. We assessed general stress, postpartum-specific stress, negative affectivity, salivary cortisol of mother, and secretory immunoglobulin A (sIgA) levels of breast milk 4-6 weeks after delivery. Controlling for the effects of women's age, weight, number, and duration of feedings, postpartum-specific stress was related to reduced sIgA concentration (R2 = .206, beta = -.275, p = .020). This study suggests that the established link between psychological stress and immunity may also extend to the immunity of the newborn by reducing the immunological benefits of breast milk. It also suggests that breastfeeding might be a potential mechanism of the relationship between maternal stress and the health of the offspring. Findings highlight the need for interventions addressing women during the postpartum period, in order to ensure the mother's well-being and the infant's optimal development.

Keywords: breastfeeding; immunity; maternal stress; sIgA.

MeSH terms

  • Adult
  • Breast Feeding
  • Female
  • Greece
  • Humans
  • Hydrocortisone / metabolism
  • Immunoglobulin A, Secretory / immunology
  • Immunoglobulin A, Secretory / metabolism*
  • Milk, Human / immunology*
  • Mothers / psychology*
  • Postpartum Period / psychology*
  • Regression Analysis
  • Stress, Psychological / immunology*
  • Stress, Psychological / metabolism
  • Young Adult


  • Immunoglobulin A, Secretory
  • Hydrocortisone