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.

Impact of prenatal stress on mother-infant dyadic behavior during the still-face paradigm.

BACKGROUND: Mother-infant interaction provides important training for the infant's ability to cope with stress and the development of resilience. Prenatal stress (PS) and its impact on the offspring's development have long been a focus of stress research, with studies highlighting both harmful and beneficial effects. The aim of the current study was to examine the possible influence of both psychological stress and hypothalamic-pituitary-adrenal (HPA) axis activity during pregnancy with mother-child dyadic behavior following stress exposure. METHODS: The behavior of 164 mother-infant dyads during the still-face situation was filmed at six months postpartum and coded into three dyadic patterns: 1) both positive, 2) infant protesting-mother positive, and 3) infant protesting-mother negative. PS exposure was assessed prenatally according to psychological measures (i.e., psychopathological, perceived and psychosocial PS; n = 164) and HPA axis activity measures (maternal salivary cortisol, i.e., cortisol decline and area under the curve with respect to ground (AUCg); n = 134). RESULTS: Mother-infant dyads in both the high- and low-stress groups showed decreasing positive and increasing negative dyadic behavior in the reunion episode, which is associated with the well-known "still-face" and "carry-over" effect. Furthermore, mother-infant dyads with higher psychosocial PS exhibited significantly more positive dyadic behavior than the low psychosocial PS group in the first play episode, but not in the reunion episode. Similarly, mother-infant dyads with high HPA axis activity (i.e. high AUCg) but steeper diurnal cortisol decline (i.e. cortisol decline) displayed significantly less negative behavior in the reunion episode than dyads with low HPA axis activity. No significant results were found for psychopathological stress and perceived stress. CONCLUSIONS: The results suggest a beneficial effect of higher psychosocial PS and higher prenatal maternal HPA axis activity in late gestation, which is in line with "stress inoculation" theories.