Understanding the relationship between disaster-related prenatal maternal stress and child motor development: The QF2011 Queensland Flood Study

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Prenatal maternal stress can have a profound and enduring influence on child development. This represents an important public health issue and signals a need for intervention. However, despite an accumulating number of empirical studies, several key questions about the effects of prenatal maternal stress remain unanswered: 1) Few studies have focused on motor development, even though it is foundational for development across a range of other areas; 2) Research on mechanisms of transmission has focused on physiological processes, such as cascades of stress related hormones, and largely ignored the psychological cascades that can drive these underlying physiological responses; 3) Many prenatal stress studies only measure child development at one point in time, which provides information about the emergence of effects but cannot answer important questions about progression; and 4) Very few prenatal stress studies have looked at variables that can explain or reduce negative effects, which is essential information for effective intervention. This thesis investigates the relationship between different aspects of disaster-related prenatal maternal stress and child motor development, explores how stress reactions work together to predict motor development, and proposes a cascade of stress reactions as a psychological mechanism of transmission for the effects of prenatal maternal stress. It examines continuity and change in findings between 16 and 30 months and, finally, looks at whether maternal coping predicts child motor development. At recruitment, mothers (N = 224) exposed to a major flood during pregnancy completed questionnaires assessing flood exposure (QFOSS), peritraumatic distress (PDI) and dissociation (PDEQ), posttraumatic stress (IESR), a cognitive appraisal of the overall flood consequences, and coping (BriefCOPE). At 16 months (N = 145) and 30 months (N = 150) post-partum, children’s fine and gross motor development was assessed using the Bayley-III, and mothers completed questionnaires assessing postnatal stressors (i.e., life events, parenting stress and mental health). At 16 months, higher maternal posttraumatic stress predicted poorer child fine motor development and negative cognitive appraisal predicted poorer gross motor development. Both effects were only significant for children exposed to the flood from mid-gestation onwards. At 30 months, higher maternal posttraumatic stress again predicted poorer child fine motor development, but the relationship between cognitive appraisal and gross motor development was no longer evident. In addition, two new effects emerged: higher maternal dissociation predicted poorer child gross motor development, and flood exposure later in gestation predicted better gross motor development. Cascades of maternal stress reactions linked flood exposure to poorer child motor development, with different mechanisms for fine and gross motor development. Coping strategies predicted motor development indirectly via maternal stress. Both positive and negative effects were evident, depending on the type of coping strategy. Overall, this thesis makes several important contributions. It extends the current literature by establishing that different types of prenatal maternal stress can predict different areas of motor development in early childhood. It proposes potential psychological mechanisms of transmission for the effects of prenatal maternal stress on motor development, and provides further evidence that the effects of prenatal maternal stress can be enduring. It is also suggests that maternal coping indirectly predicts child development by influencing maternal stress. These findings have implications for the design of prenatal stress research, and for guiding interventions with pregnant mothers in the wake of natural disasters.