Background: The magnitude of maternal mortality is underestimated as deaths occurring beyond the traditional 42-day time period after the pregnancy ending ('late death') have not been reported routinely in Australia.
Aims: The aims of this study were to undertake a data linkage study to improve the ascertainment of maternal deaths and to determine the number of deaths occurring 43-365 days after the pregnancy ended ('late maternal death').
Methods: Data from the New South Wales Midwives Data Collection were linked with the Australian Institute of Health and Welfare National Death Index. Australian identified pregnancy-related deaths were then coded as direct, indirect and incidental to the pregnancy.
Results: During the period 1994-2001, 173 maternal deaths were identified. Of these, 97 were classified as occurring up to 42 days of the pregnancy ending, 15 (15.5%) of which were previously unknown to the maternal mortality committee. In addition, 76 deaths were classified as occurring between 43 and 365 days after the pregnancy ended. The majority (70 of 76) of these late deaths were only identified through the linkage study. Most (73 of 76) of these deaths were classified as indirect maternal deaths with the most common causes of deaths suicide (n= 23), cardiac disorders (n= 16) or accident/violence (n= 16).
Conclusions: The ascertainment of maternal and late maternal mortality was enhanced through data linkage of birth and mortality data. Data linkage is a viable method for monitoring late maternal deaths.