Influence of mothers' stress on their infants' stress level: A preliminary study.

Background: In a previous study, mothers' stress was demonstrated to affect the stress of their infants. However, stress is a multi-layered concept, and there is a lack of studies on the type of stress that influences infant stress.

Objective: This study examined how various types of mothers' stress influence their infants' stress by measuring stress that emanates from COVID-19, child rearing, and stress levels based on speech and cortisol in saliva.

Methods: This study was conducted in two phases, and the stress of 21 mother-infant dyad were evaluated using questionnaires, participants' saliva, and voice recording.

Results: The results demonstrated that maternal stress increased infant stress, rearing stress decreased infant stress, and COVID-19 stress did not affect infant stress. Furthermore, there was no relationship between stress measured using questionnaires and stress measured using saliva, indicating that these factors independently affect infant stress.

Conclusion: It is clear that stress is multi-layered and that it is necessary to grasp each of the various stresses and their relationship appropriately.