Preventing stillbirths: Better data to inform interventions in Australia

Abstract

Background In Australia, one in every 139 women reaching 20 weeks gestation will have a stillborn baby. There is significant disparity in stillbirth rates within subgroups of the Australian population. Among Aboriginal and Torres Strait Islander (Indigenous) women, the stillbirth rate is one in every 93 women reaching 20 weeks gestation. Unfortunately, there has been no reduction in the national stillbirth rates over the past two decades and nearly a third are ‘unexplained’. The ability to identify women at increased risk of stillbirth is an important and challenging priority. At present in Australia, there is a paucity of high quality data on causes and contributing factors to stillbirth. Furthermore, inconsistent approaches to investigation and classification affect the quality of data on causes of death and hamper the development of effective interventions to prevent stillbirth. Aims The primary aim of this Thesis is to describe the epidemiology of stillbirth within the Australian context. This aim was addressed by: • Examining trends in stillbirth by clinical classification of cause of death, Indigenous status and gestational age, to identify focal areas for preventive efforts • Assessing gestational age specific risk of stillbirth associated with four important contributors (diabetes, hypertension, antepartum haemorrhage and small-for-gestational age) to higher stillbirth rates among Indigenous women in order to identify periods of increased risk • Developing and validating a statistical model to predict the risk of antepartum stillbirth at term (≥37 weeks) using maternal and pregnancy factors as a potential decision-making aid for clinicians and women • Assessing consistency in application of the Perinatal Society of Australia and New Zealand Perinatal Death Classification system between hospital committees and an independent expert panel, to identify areas for quality improvement • Determining maternal and pregnancy factors associated with parental consent to autopsy following stillbirth and explore parents’ views and experiences of the autopsy consent process to inform clinical practice Methods and Results Data for 1995-2011 (n=881,211 singleton births) from the Queensland Perinatal Data Collection was analysed to address the first three aims. Stillbirth trends analysis found consistently higher rates of stillbirth among Indigenous women, however, the gap in stillbirth rates had narrowed. Gestational age specific stillbirth risk analysis found disparity in the magnitude of stillbirth risk for pre-existing diabetes and small-for-gestational age between Indigenous and non-Indigenous women. Despite strong association between maternal clinical factors and antepartum stillbirth risk, the prediction model had a poor ability to predict stillbirth risk at term. Consistency in application of the perinatal death classification system was assessed by calculating agreement. A substantial level of agreement was found between hospital committee and expert panel review of a cohort of 217 stillbirth cases, however, low levels of agreement were found for the categories of antepartum haemorrhage and fetal growth restriction. Parents’ lived experiences were explored using mixed methods. The study identified maternal and pregnancy characteristics associated with consent or decline of autopsy following stillbirth; likewise the in-depth interviews revealed that the autopsy consenting process was part of a larger bereavement journey for parents. Parents expected healthcare professionals to have an appreciation for their loss and provide bereavement care in a sensitive and respectful manner. Conclusions These studies highlight the need for early detection and management of pre-existing medical conditions as well as improving equitable access to high quality antenatal care. Of continued concern are stillbirths which remain unexplained after investigation. Numerous factors influence parents’ decision making around stillbirth autopsy and sensitivity and respectfulness in particular on the part of healthcare providers is essential.