The impact of precarious employment in early adulthood on age at first childbirth: development of theoretical, methodological and analytical frameworks from a life course perspective.

Abstract

The average age of Australian women at first childbirth in 2006 was 28.2 years, while the proportion of first births among women aged ≥ 35 years increased from 8% in 1997 to 14% in 2006. From a public health perspective, this shift has a raft of health consequences for women and children, including increased risks of miscarriage, gestational diabetes, and birth defects in the child. Furthermore, the use of assisted reproductive technologies associated with older childbearing carries risks in pregnancy, and adverse outcomes in offspring, in addition to very significant financial and emotional costs. Thus, it is imperative to understand barriers to childbearing at ‘optimal’ ages. Since evidence also suggests women now have fewer children than they would like, it is particularly important to investigate underlying structural determinants of older motherhood and foreshortened reproductive careers. Precarious employment conditions, related to trends in international labour markets, may play an important role in older age of first-time motherhood (as suggested in contemporary fertility theories). However there is a paucity of Australian research about this issue. A post-positivist approach was used to design a theory incorporating multiple disciplinary perspectives. The theory sought to explain the influence of macro-economic factors on individual lives, and was cognisant of the life course dimension. The ensuing conceptual framework and research questions guided the design of a retrospective cross-sectional study based on a birth cohort (n ~ 1000, born 1973-75) which was established when women were aged ~ 30 years. A detailed event history instrument was developed to obtain data regarding a range of life domains including pregnancy, partnering, education, and employment (sometimes as detailed as monthly intervals). Time-varying and time-constant survival analysis techniques were applied within a life course framework to examine the effects of precarious employment on age at first childbirth (taking into account educational attainment and other influential factors), with a sub-set of the study cohort (n=230). This project is innovative at a number of levels. For the first time within the public health domain, an argument is presented for the relevance and significance of the contemporary social issue of older age at first childbirth. From an epidemiological perspective, the project offers advances in a number of areas, including theory-building (particularly in the convergence of life course and hierarchical perspectives) and engagement with a relatively new exposure variable (precarious employment). The project contributes substantially to the sub-discipline of life course epidemiology, in the following ways: (1) collection of fine-grained life course data (event history data as opposed to cross-sectional or successive point-in-time measures); (2) improvement of techniques to collect high quality retrospective data (type of survey instruments and fieldwork procedures); and (3) presentation of a framework for the use of survival analysis techniques to complement life course theories. This PhD thesis presents and discusses each stage of project development and execution, including theory-building, survey design, fieldwork, and construction of the analysis framework, culminating in a description of preliminary data analyses conducted (n=230) and results obtained. In this thesis the intellectual contributions arise from the combined work on theoretical, methodological and analytical frameworks. They will form the basis of future (postdoctoral) analyses to be conducted with the entire dataset. Results from this project will contribute to the growing evidence base highlighting detrimental impacts of globalisation and recent changes to labour market institutions on the lives of individuals. Ultimately the study findings may help to shape policy which enables women and their partners to have children (if desired) at a time in the life course which is most conducive to their health and to the health of their children.