A soft baby carrier intervention enhances amygdala responses to infant crying in fathers: A randomized controlled trial

Madelon M.E Riem,Anna M Lotz,Lisa I Horstman,Maaike Cima,Martine W.F.T Verhees,Kim Alyousefi-Van Dijk,Marinus H Van Ijzendoorn,Marian J Bakermans-Kranenburg

doi:10.1016/j.psyneuen.2021.105380

Abstract

New fathers may grow into their parental role through active involvement in childcare. Spending time in physical contact with the child may promote an adaptive transition to fatherhood. In this randomized controlled trial, we tested the effects of a baby carrier intervention on fathers’ hormonal and neural functioning. Using functional magnetic resonance imaging (fMRI), we examined whether infant carrying affects neural reactivity to infant crying in first-time fathers, taking into account the role of the hormone oxytocin as a mediating mechanism and fathers’ own childhood experiences as a potential moderating factor. Sixty first-time fathers (infant age M = 11.18 weeks, SD = 2.08) were randomly assigned to a baby carrier intervention group (n = 32 fathers) or a control group (n = 28 fathers). Fathers in the intervention group were instructed to use a baby carrier for three weeks, whereas fathers in the control group were instructed to use a baby seat. Before and after the intervention salivary oxytocin was measured and neural reactivity to infant crying was assessed using fMRI. Results showed that the infant carrier intervention increased amygdala reactivity to infant crying compared to the infant seat users. This effect was most pronounced in fathers with experiences of childhood abuse. The carrier intervention did not affect fathers’ oxytocin levels. Our findings indicate that spending time in physical contact with the infant may promote attention to and accurate perception of infant signals, in particular in fathers with more adverse childhood experiences. Soft baby carriers may, therefore, facilitate an adaptive transition to fatherhood.

Highlights

Research on parenting has predominately focused on mothers and neglected the role of fathers for a long time
OT-AUCchange was entered as mediator, because we aimed to test whether change in oxytocin level after the use of the baby carrier mediated the effect of the intervention on neural reactivity
ROI analyses revealed that fathers in the control and carrier group showed significant activity in the amygdala, inferior frontal gyrus (IFG), insula, middle and superior temporal gyrus, and middle frontal gyrus (MFG) during exposure to crying compared to control sounds at the pre-test as well as the post-test, threshold-free cluster enhancement (TFCE)-familywise error corrected, see Table 1 and Fig. 2

Summary

Introduction

Research on parenting has predominately focused on mothers and neglected the role of fathers for a long time. In contrast to mothers who undergo strong hormonal changes during pregnancy and labor, fathers may adapt to their new parental role more slowly through active involvement in childcare (Abraham et al, 2014). In the current randomized controlled trial (RCT), we examined the effects of a baby carrier inter vention on fathers’ hormonal and neural functioning. Using fMRI, we aim to test whether carrying an infant for at least six hours per week, for three weeks, affects neural reactivity to infant crying in first-time fa thers, examining the role of the hormone oxytocin as a potential medi ating mechanism and fathers’ own childhood experiences as a potential moderating factor

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