Cold pressor stress reduces left cradling preference in nulliparous human females.

The left cradling preference refers to the finding that women hold their infants more frequently on the left side of their own bodies. Several observational studies showed reduced left cradling during stressful circumstances, such as mother-infant separation, or domestic violence. However, until now no experimental study was conducted to investigate the immediate impact of stress on cradling behaviour. Half of the 64 female subjects participating were randomly assigned to a stressful bilateral cold pressor test. The remaining subjects performed a non-stressful control procedure. Before and after this intervention, cradling behaviour was assessed using a baby-like doll. Subjects showed a left cradling preference prior to the intervention. The cold pressor test increased blood pressure and heart rate significantly. A repeated ANOVA revealed an interaction of intervention (cold pressor vs. control) X assessment period (pre- vs. post-intervention), indicating that cold pressor stress reduces left cradling behaviour in female volunteers. Our data indicate that stress influences cradling preference. This may be of relevance for caregiver-infant interactions.