Effects of a Baby Carrier Intervention on Fathers' Sensitivity, Involvement, and Hormonal Levels: Follow-Up of a Randomized Controlled Study.

Objective. Fathers are of great importance for healthy child development. This randomized controlled study investigated the longer-term effects of an intervention using a soft baby carrier on fathers' observed sensitive caregiving, involvement, and oxytocin and cortisol levels. Design. First-time fathers were randomly assigned to use a baby carrier (n = 41) or baby seat (n = 39) and were asked to use the carrier or seat for at least 6 h per week for 3 weeks. Pretest (M _{child age}  = 2.67 months), posttest (M _{child age}  = 3.99 months), and follow-up (M _{child age}  = 8.25 months) father data were collected. Results. No intervention effects of baby carrier use on fathers' sensitivity, involvement, and oxytocin or cortisol levels at follow-up emerged. Unexpectedly, fathers in the baby seat condition reported an increase in the amount of time spent with the infant. Fathers' sensitivity and oxytocin levels decreased over time, while cortisol levels increased over time, irrespective of condition. Conclusions. This study showed less optimal hormonal levels in fathers over time, suggesting that support during the first months of fatherhood is needed. Furthermore, use of a baby seat may have contributed to fathers enjoying their time with their infant and consequently their involvement in child caregiving.