Gewoontes in de Opvoeding van Baby's

This quasi-randomized controlled trial assessed effects of four parallel conditions in a two-by-two design (indoor vs. outdoor and pram vs. carrying) on infant cortisol and sleep as well as maternal cortisol and mood. The mother-infant dyads were invited to the lab between 12:00 and 18:00 hours. Mothers filled in questionnaires on demographics. Then, mothers were asked to give their infant a ‘mock bath’ for 12 minutes. Instructions were to undress, change the diaper, ‘wash’ with a dry cloth (chest and back), and then weigh and dress the infant. Previous research indicates that diaper changes and handling induce elevations of infants’ cortisol (Jansen et al., 2010). The researcher left the room, and the task was videotaped. After the task, dyads were randomly allocated by drawing a sealed envelope to one of the following conditions for a duration of 30 minutes: Walking outdoors with the infant in a pram (OP), or in a chest carrier (OC), or staying indoors, with the infant in a pram (IP), or in a chest carrier (IC). We tested for group differences in the following variables, in which case the variable would be considered as a covariate: infant sex (boy or girl), infant and maternal age, maternal ethnicity (European or non-European), highest completed maternal education (lower = up to secondary (vocational) education - Dutch VWO/MBO; higher = college or university), time of day at the start of the condition measured in minutes after noon (12:00), temperature at the start of the conditions, and season. Mothers’ steps during the condition were measured in order to confirm that mothers walked more steps during the outdoor conditions. Salivary samples reflect cortisol concentrations of 25 minutes prior to sampling (Dickerson & Kemeny, 2004; Jansen et al., 2010). Saliva was sampled from mothers and infants at arrival to the lab (T0, reflects 25 minutes before arrival), and after the stressor at: 0 minutes (T1, reflects baseline), at 20 minutes (T2, just before starting the condition; reflects expected stress-peak), at 55 minutes (T3, reflects minute 10 of the condition) and at 70 minutes (T4, reflects minute 25 of the condition). The duration of infant sleep during the conditions was reported by the mothers in minutes, ranging from 0 to 30 minutes. Maternal mood was assessed through the ‘Global Vigor and Affect Scale’ (Monk, 1989) after the stressor and after the conditions. This dataset includes demographics, mother- and infant cortisol, details on the conditions (e.g. weather), infant sleep and maternal mood. Videotapes of the stressor are not shared.