Physiological linkage in pregnancy: Couples' cortisol, negative conflict behavior, and postpartum depression.

Within-couple concordance in momentary cortisol levels ("cortisol linkage") may reflect meaningful relationship dynamics. In this study, we examined couple cortisol linkage during pregnancy, associations with negative conflict couple behavior, and subsequent postpartum depressive symptoms. Eighty-two opposite-sex couples expecting their first child engaged in a conflict discussion, provided six salivary cortisol samples over the course of a laboratory visit, and then reported on depressive symptoms six months after their baby's birth. Couples' cortisol levels were significantly positively associated with each other, indicating linkage. When mothers and fathers behaved less negatively during the prenatal conflict discussion, they exhibited stronger couple cortisol linkage. Stronger cortisol linkage also predicted fewer postpartum depressive symptoms for fathers. Negative conflict behavior did not moderate the association between cortisol linkage and postpartum depression. These findings suggest that stronger physiological associations between partners during pregnancy may reflect healthier relationship interactions and be beneficial to fathers' postpartum mental health.