The association between breastfeeding, the stress response, inflammation, and postpartum depression during the postpartum period: Prospective cohort study

BackgroundResearch suggests that exclusive breastfeeding may have a stress-protective role in postpartum depression; however, less is known about the underlying mechanisms by which this protection may occur or whether the protective relationship holds for women who mix breast and bottle feeding.ObjectivesTo examine patterns of the stress response, inflammation, and depressive symptoms among women predominantly breastfeeding or bottle feeding their infants at 6 months postpartum.DesignA part of a larger longitudinal study across 6 months postpartum investigating the psychoneuroimmunology (PNI) of postpartum depression.SettingPrenatal clinics and community.ParticipantsOne hundred nineteen postpartum women who met inclusion/exclusion criteria and followed up from the prenatal period to postpartum 6 months.MethodsData were collected during seven home visits occurring during the 3rd trimester (weeks 32–36) and on postpartum days 7 and 14, months 1, 2, 3, and 6. Women completed stress and depression surveys and provided blood for pro- (IL-1β, IL-6, IL-8, TNF-a, IFN-γ) and anti-inflammatory (IL-10) cytokines, and collected saliva for diurnal cortisol.ResultsSelf-report of predominant breastfeeding during 6 months postpartum ranged from 91.9% at day 7 to 70.6% at month 6 postpartum. There were no associations between the pattern of feeding and depressive symptoms. Biological differences, however, existed between the groups, with levels of salivary cortisol at 8 AM and 8:30 AM at month 6 higher and levels of IL-6 at month 6 lower in women who primarily breastfed compared to those who primarily bottle fed their infants after controlling for confounding variables.ConclusionsBreastfeeding was not related to postpartum depression however differences in stress and inflammatory markers are apparent at month 6 postpartum.