Impact of prenatal stress on the dyadic behavior of mothers and their 6-month-old infants during a play situation: role of different dimensions of stress

Prenatal stress (PS) is an established risk factor in the etiology of mental disorders. Although mother–child interaction is the infant’s first important training in dealing with stress, little is yet known about the impact of PS on mother–infant dyadic behavior. The current study aimed to elucidate the prospective influence of psychological and physiological stresses during pregnancy on mother–infant dyadic behavior. Mother–infant interactions were videotaped at 6-month postpartum and coded into three dyadic patterns: (1) both positive; (2) infant protesting–mother positive; and (3) infant protesting–mother negative, using the infant and caregiver engagement phases. Exposure to PS was assessed during pregnancy using psychological (i.e., psychopathological, perceived, and psychosocial PS; n = 164) and physiological stress measures (i.e., maternal cortisol; n = 134). Group comparisons showed that psychosocial PS was predictive of mother–infant behavior at 6-month postpartum, indicating that dyads of prenatally high-stressed mothers exhibited significantly more positive interaction patterns (i.e., infant positive–mother positive) as compared to the prenatally low-stressed group. Physiological PS was unrelated to mother–infant behavior. These results suggest that mild psychosocial PS may be advantageous for positive mother–infant dyadic behavior, which is in accordance with the stress-inoculation model that assumes a beneficial effect of PS.