Inequalities in pregnancy outcome: a review of psychosocial and behavioural mediators.

The purpose of this paper is to review the literature on psychosocial factors in pregnancy outcome and to present a model which attempts to integrate the findings theoretically. There are four sections. The first presents published data on the incidence of early childhood mortality and low birth weight. Changes over time and differences between countries are noted and attention is drawn to the marked inequalities between occupational groups in the British data. The second section reviews the evidence that a variety of psychosocial risk factors influence pregnancy outcome, notably social, emotional, cognitive and behavioural factors. The third section develops the theme of inequalities and examines theories which have been advanced to account for the differences in adult mortality. We argue that material deprivation goes some way towards explaining inequalities in pregnancy outcome, but that any proper account will have to explain the links between inputs and outcomes--the processes and mechanisms by which material deprivation is translated into observable mortality and morbidity. In the concluding section, we argue that some of the principal links are the psychosocial risk factors described in the second section, and we present a model which traces the pathways of mediation.