437Comparison of stillbirth trends in Wales and Western Australia using pooled routinely collected health data

Abstract

Abstract Background As there are variations in stillbirth rates and trends, even among high income countries, international comparisons can provide insights into how reductions in stillbirths can be achieved. We compared stillbirth rates and trends over time in Wales and Western Australia (WA). Methods We pooled population-based data of all births of at least 24 weeks’ gestation occurring between 1993-2015 in Wales and WA, divided into 6 time-periods. The stillbirth rate per 1,000 births was estimated for each cohort in each time-period. Multivariable Poisson regression analyses, were performed to evaluate the interaction between cohort and time-period. relative risk (RRs) and 95% Confidence Intervals (CIs) for each time-period and cohort were calculated. Results The overall stillbirth rate declined by 15.9% in Wales and 40.4% in WA. Using WA and 1993-1996 as the reference group, the adjusted RRs for stillbirths at 39-41 weeks’ gestation in the most recent study period (2013-15) were 0.85 (95% CI 0.64 to 1.13) in Wales and 0.51 (95% CI 0.36 to 0.73) in WA. Conclusions The stillbirth rate disparities between Wales and WA have widened in the last two decades (especially among term births). Some of these differences may be partially explained by maternal lifestyle behaviours such as smoking, but we had insufficient population-level data to investigate their contribution. Key messages The stillbirth rate was persistently higher in Wales than WA from 1993 to 2015, with widening disparities after adjustment for important risk factors.