Difficult temperament, breastfeeding, and their mutual prospective effects: the Norwegian Mother and Child Cohort...

(1) To examine the extent to which difficult temperament and breastfeeding are associated at child age 6 and 18 months. (2) To examine longitudinally whether breastfeeding has an influence on temperament development or whether difficult temperament has an influence on continued breastfeeding.

This prospective study is part of the Norwegian Mother and Child Cohort Study, which targets all women giving birth in Norway; the present sample comprises 30,466 children. Mothers reported on child difficult temperament at child age 6 and 18 months and on breastfeeding from 0 to 6 months and from 6 to 12-14 months. Prospective associations between breastfeeding and difficult temperament were examined using structural equation modeling, with comparison of cross-lagged pathways. All analyses were adjusted for background variables that are relevant for breastfeeding.

At 6 months, children with more difficult temperament were significantly less likely to have been "fully" breastfed (exclusively and predominantly breastfed) for the recommended period of 6 months (unadjusted point-biserial correlation r pb = -.15; adjusted r pb = -.11). At 12 to 14 months, there was no longer an association between difficult temperament and (continued) breastfeeding after adjusting for background variables, temperament, and breastfeeding at 6 months. The cross-lagged analyses of the longitudinal pathways yielded negligible effects of difficult temperament on later breastfeeding and of breastfeeding on later temperament.

Difficult temperament and reduced breastfeeding seem to be associated only during the first half-year of the child's life. After that, we found no evidence of codevelopment between difficult temperament and breastfeeding.