Maternal Experiences of Childhood Maltreatment Moderate Patterns of Mother-Infant Cortisol Regulation Under Stress

• In Event: Risk and Protective Factors in the Regulation of Maternal and Infant Cortisol

Abstract

Introduction: The relation between maternal and infant cortisol responses has been a subject of intense research interest over the past decade (e.g., Atkinson et al., 2013; Hibel et al., 2015; Laurent et al., 2011). The growing nature of this field has resulted in numerous methodological and statistical methods of characterizing the associations between mother and infant cortisol. Further, studies have begun to examine risk factors that adversely affect mother-infant stress regulation. In particular, Buss et al. (2017) hypothesized that maternal experiences of childhood maltreatment (CM) are important in dysregulating stress responsivity across generations.
Aims and Hypotheses: The aims of the study were to assess whether maternal CM moderated four types of relations between maternal and infant cortisol: 1) overall associations between maternal cortisol and infant cortisol, 2) changes in maternal and infant cortisol levels over the course of a stressor; 3) patterns of absolute differences between maternal and infant cortisol; and 4) cross-lagged associations between mother and infant cortisol. Hypothesis 1: We expected that higher levels of CM would be related to lower concurrent associations between mother and infant cortisol. Hypothesis 2: We expected that, for both mothers and infants, patterns of cortisol response over time to the stressor would be moderated by CM. Hypothesis 3: We hypothesized that higher CM would also be associated with larger absolute mother-infant differences in cortisol levels over the course of the stressor. Hypothesis 4: We hypothesized that reciprocal patterns of physiological influence in the dyad would occur but would be moderated by maternal CM.
Methods: 150 mother-infant dyads (45% male) participated in the Mother-Infant Neurobiological Development (MIND) study. Maternal experiences of childhood maltreatment were assessed by the well-validated Maltreatment and Abuse Chronology of Exposure scale (MACE; Teicher & Parigger, 2011). At infant age 4 months, dyads completed the Still-Face Paradigm (SFP; Tronick et al., 1978). Saliva was assayed for cortisol at three timepoints: baseline, 20 mins post-stressor, and 40 mins post-stressor. Multilevel modeling, dyadic repeated measures modelling, and stability-influence modeling was conducted in R.
Results: Results indicate that maternal CM moderated cortisol patterns in several ways. First, lower-CM mothers and infants had strong positive associations between cortisol levels measured at the same time point, while higher-CM mothers and infants did not show significant correlations. Second, infants of higher-CM mothers had cortisol levels that were moderately high and remained elevated over the procedure, while infants of lower-CM mothers had decreasing cortisol levels over time (Figure 1). Third, higher-CM mothers and infants showed increasingly divergent cortisol levels over time, while lower-CM dyads showed more convergent cortisol levels over time. Finally, patterns of cross-lagged influence of infant cortisol on subsequent maternal cortisol were moderated by CM, such that lower-CM mothers were influenced by their infants’ cortisol levels at earlier time points than higher-CM mothers.
Conclusions: These findings point to the importance of the mother’s CM as one contributor to early processes of stress regulation in the mother-infant dyad and begin to model the transmission of dysregulated stress responses across generations.

Authors

• Jennifer E. Khoury, McMaster University
  Presenting Author

• Joseph Beeney, University of Pittsburgh
  Non-Presenting Author

• Ilana Shiff, York University
  Non-Presenting Author

• Michelle Bosquet Enlow, Harvard Medical School
  Non-Presenting Author

• Karlen Lyons-Ruth, Harvard Medical School
  Non-Presenting Author