Maternal Engagement and Newborn Characteristics in Association with Mothers’ Physiological Dynamics While Soothing an Infant

• In Event: The Conflicts and Balances of Parents’ Reactivity to Caregiving Demands and Parenting: A Developmental Lens

Abstract

Introduction: Soothing a distressed infant is a common parenting challenge, and a physiologically taxing one. Parents who regulate their own physiology effectively are more likely to provide positive caregiving, such as greater sensitivity to the infant needs (Moore et al., 2009). However, not all parents are equally disturbed by a distressed infant (Jones-Mason et al., 2018), and there have been few efforts devoted to understanding the contributing factors. Applying dynamic systems analyses, the present study investigated whether maternal engagement during distressing and non-distressing situations with the infant would be differentially associated with mothers’ physiological dysregulation. Moreover, we tested whether newborn attention, an innate infant characteristic of sustained alertness, moderated the link between maternal engagement and maternal physiological dynamics.

Method: Data for the present study were from 155 newborn infants (77 males, 47.5%) and their mothers at 7 months postpartum. The attention subscale of the NICU Network Neurobehavioral Scale (Lester & Tronick, 2004), administered shortly after birth, was used as the index of infant characteristics. This scale captures infants’ ability to attend and respond to auditory and visual simulation. Mothers and their 7-month-old infants returned to the laboratory and completed the still-face paradigm (Haley & Stansbury, 2003), a commonly used paradigm to elicit infant distress. After an initial free play period (i.e., Play episode), mothers were instructed to maintain a flat affect for two minutes and then resume their interactions with the baby for another two minutes (i.e., the Reunion episode).

Mothers’ respiratory sinus arrhythmia (RSA)—a measure of parasympathetic regulation of cardiac arousal—were recorded in 30-s epochs as the index of physiological reactivity and regulation. Moreover, mothers’ positive engagement with the infant during the Play, as well as the Reunion episode, was coded second-by-second using the Infant and Caregiver Engagement Phases system (Weinberg & Tronick, 1999). Positive maternal engagement was calculated as the proportion of time the mother was coded as exhibiting social monitor (positive vocalizations) and positive engagement.

Results: Nonlinear dynamic systems models were fitted for maternal RSA, with discrete changes as outcomes. The homeostatic point (i.e., typical levels of a mother’s RSA) and return strength (i.e., the rate at which maternal RSA return to homeostasis after being perturbed) were identified by these models. As presented in Table 1 mothers’ RSA return strength became weaker from Play to Reunion (b = 0.53, SE = 0.08, p < .001), indicating a slower return to the homeostatic point, therefore a more disturbed parasympathetic regulation. Interestingly, mothers who were more positively engaged during Play showed more physiological disturbance, compared to the less engaged mothers (b = 1.61, SE = 0.72, p = .03). Mothers’ positive engagement during Reunion, however, did not show the same effect. Additionally, mothers of infants who are more attentive at birth showed a larger decrease in RSA return strength (b = 0.25, SE = 0.08, p = .004). However, newborn attention and maternal engagement did not interact to influence maternal RSA return strength. Implications for the physiological foundations of early caregiving will be discussed.

Authors

• Mengyu (Miranda) Gao, Faculty of Psychology, Beijing Normal University, China
  Presenting Author

• Sheila E Crowell, University of Utah

• Liz Conradt, Duke University