Date of Award
Master of Science
School of Nursing and Public Health
Faculty of Computing, Health and Science
In April 2000 the Western Australian Birth Defects Registry held its 20th Anniversary Scientific Symposium to signify the first 20 years of the Birth Defects Registry in Western Australia. At the Symposium, significant trends and occurrences in birth defects within Western Australia over the past 20 years were addressed. One factor highlighted in the Registry's 1980-1999 report was that birth defects were reported less frequently in rural regions compared with metropolitan areas. Data collected from the metropolitan area is considered by the Birth Defects Registry to be the most accurate. Therefore, incidence rates of birth defects in this area arc used as a benchmark for determining the incidence of birth defects throughout Western Australia. The aim of this study was to explore the lower incidence of birth defects in the Midwest of Western Australia compared with that of metropolitan Western Australia. The study investigated if the observed lower incidence of birth defects in the Midwest was due to case under reporting. The study target population included newborns whose mothers were Midwest residents at the time of their birth between the years of 1995 - 1999. A mixed methodological approach, combining capture-recapture and thematic analysis was used. The study was conducted in two phases. The first phase involved the collection of quantitative data. The potential target population in the Midwest consisted of 5066 births. A sample of 440 newborn case notes were selected randomly from the target population and accessed from client files held at Geraldton Regional Hospital. A record was made of any reportable birth defects. The result provided demographic and descriptive statistics, which were compared with data held by the Birth Defects Registry regarding the Midwest. This mode of sample collection is known as capture-recapture methodology. Comparison of data from the sample with data from the Registry was used to document the existence of discrepancies and to enable an ascertainment-adjusted analysis to be performed. To address the study's aims, the ascertainment adjusted rate was compared with the rates occurring in the metropolitan area. In Phase 1, quantitative findings showed the lower incidence of birth defects diagnosed in infants during the newborn period in the Midwest of Western Australia was unlikely to be due to case under reporting. Possible factors contributing to the lower incidence of birth defects in the Midwest compared to the Metropolitan area were discussed. These include the lower maternal age of Midwest mothers, a higher Aboriginal population, study sample bias and case under-reporting beyond the newborn period. Full exploration of these issues, however, was outside the scope of this study and is an area for future research. The second phase of the study involved collection of qualitative data. Health professionals reporting birth defects in the Midwest were asked to participate in focus group interviews. Three groups of health professionals were targeted: general practitioners; midwives; and child health nurses. Interview responses were transcribed and indexed according to common themes and issues. This analysis provided insight into the cause of empirical findings and discrepancies, allowing for recommendations focused on improving and/or sustaining birth defect notification practices of health professionals in the Midwest of Western Australia. Findings showed that a knowledge deficit regarding the reporting of birth defects exists in targeted Midwest health professionals. Possible reasons for the knowledge deficit included high transfer rates of newborns affected by birth defects, uncertainty regarding the responsibility of birth defect reporting, limited use of birth defect notification cards by health professionals and the lack of ongoing education and promotion of birth defects in the Midwest Region. Study recommendations include further research to explore factors contributing to the lower incidence of birth defects in the Midwest, education and promotion regarding birth defects and the role of the Birth Defects Registry, amending and centralising birth defect notification cards, and legislating the reporting of birth defects in Western Australia.
Baker, D. (2003). Clarifying The Lower Incidence Of Birth Defects In The Midwest Of Western Australia : A Study Using Capture Re-capture Methodology. Retrieved from http://ro.ecu.edu.au/theses/1489