Psychological factors, immunocompetence, and health of breast-feeding mothers and their infants.

We investigated whether the use of humor as a coping device and psychological hardiness were related to IgA levels in the saliva and breast milk of mothers, and if these factors were related to the incidence of upper respiratory infection (URI) in the mothers and their newborns. Nineteen mothers volunteered to participate and met the qualifications; however, only 17 completed all phases of the study. Prior to the birth of their child, mothers filled out demographic questionnaires and the psychological inventories. Saliva and milk samples were taken within 1 week after delivery, and follow-up questionnaires were mailed out 2 months after delivery. Coping humor was inversely related to URI incidence in both the mothers and the infants. Hardiness was directly related to coping humor and inversely related to URI incidence in the infants. Older mothers had higher coping humor and hardiness scores and fewer URIs in themselves and their infants.