Allostatic load: A theoretical model for understanding the relationship between maternal posttraumatic stress disorder and adverse birth outcomes.

Background: Adverse birth outcomes such as preterm birth and low birth weight are significant public health concerns and contribute to neonatal morbidity and mortality. Studies have increasingly been exploring the predictive effects of maternal posttraumatic stress disorder (PTSD) on adverse birth outcomes. However, the biological mechanisms by which maternal PTSD affects birth outcomes are not well understood. Allostatic load refers to the cumulative dysregulations of the multiple physiological systems as a response to multiple social-ecological levels of chronic stress. Allostatic load has been well documented in relation to both chronic stress and adverse health outcomes in non-pregnant populations. However, the mediating role of allostatic load is less understood when it comes to maternal PTSD and adverse birth outcomes.

Objective: To propose a theoretical model that depicts how allostatic load could mediate the impact of maternal PTSD on birth outcomes.

Method: We followed the procedures for theory synthesis approach described by Walker and Avant (2011), including specifying focal concepts, identifying related factors and relationships, and constructing an integrated representation. We first present a theoretical overview of the allostatic load theory and the other 4 relevant theoretical models. Then we provide a brief narrative review of literature that empirically supports the propositions of the integrated model. Finally, we describe our theoretical model.

Findings/conclusions: The theoretical model synthesized has the potential to advance perinatal research by delineating multiple biomarkers to be used in future. After it is well validated, it could be utilized as the theoretical basis for health care professionals to identify high-risk women by evaluating their experiences of psychosocial and traumatic stress and to develop and evaluate service delivery and clinical interventions that might modify maternal perceptions or experiences of stress and eliminate their impacts on adverse birth outcomes.