A mixed-method investigation of maternal cyclone exposure and perinatal health outcomes in Queensland, Australia

Abstract

Exposure to disasters during pregnancy is associated with pregnancy complications, adverse birth outcomes, and disease in adulthood. Despite Australia's disaster vulnerability, there is limited research into the impact on pregnant women and even more limited advice on how they can best prepare. In this thesis, I present the first mixed-method investigation into an association between tropical cyclones (TCs) and adverse perinatal outcomes in Australia. Population-level analysis was conducted using administrative health records and individual experiences were captured using an online survey and semi-structured interviews. I used data on over 600,000 Queensland births to explore an association between multiple TC events and population outcomes. Using Geographic Information System (GIS) methods, spatiotemporal analysis supported significant variation in perinatal outcomes across the state. This highlighted the importance of maternal location, particularly in remote areas. Using logistic multi-level modelling, I found mothers in TC-affected areas during early pregnancy had significantly higher odds of preterm births [OR = 1.29, p = 0.001] while higher odds of low birthweight births were associated with mid-pregnancy [OR = 1.62, p = 0.016]. Early pregnancy was also associated with a significant increase in the proportion of male births in affected areas [IRR = 1.08, p = 0.041] supporting the differential loss of females in utero. Exploring individual experiences of pregnancy during TCs in Australia, a survey of 90 mothers found they reported relatively low mean perceived stress. However, higher stress was found when maternal country of birth interacted with objective hardship. Interviews with 12 mothers highlighted the important role of social support networks and local knowledge in managing maternal risk perception which aligned with the moderating effects of country of birth. As the survey and interview samples were small and subject to recall and sampling bias, they were not representative of Queensland mothers. However, they provided crucial insights into individual maternal experiences within Australia. My thesis results are consistent with a significant association between severe TC events and an increase in adverse birth outcomes within an Australian population. Capturing individual experiences added an essential narrative to population trends. Though severe TCs were associated with significant changes in population outcomes, mothers utilised support networks and local knowledge to manage stress in disaster events. Such adaptive strategies could be used to continue building disaster resilience in this priority group. Throughout my project, I have identified, developed, and applied methods for effectively combining a large-scale natural experiment and qualitative research. In addition to policy recommendations made in this thesis, my findings will guide further research into pregnancy during the different disasters and crises we are yet to face. Show more