Comparison of stillbirth trends over two decades in Wales, United Kingdom and Western Australia: An international retrospective cohort study

Abstract

Background: Stillbirth is a critical public health issue worldwide. While the rates in high-income countries are relatively low, there are persistent between-country disparities.Objectives: To compare stillbirth rates and trends in Wales and the State of Western Australia (WA), Australia, and provide insights into any differences. Methods:In this international retrospective cohort study, we pooled populationbased data collections of all births ≥24 weeks' gestation (excluding terminations for congenital anomalies) between 1993 and 2015, divided into six time periods. The stillbirth rate per 1000 births was estimated for each cohort in each time period.Multivariable Poisson regression analyses, adjusted for appropriateness of growth, socio-economic status, maternal age, and multiple birth, were performed to evaluate the interaction between cohort and time period. Relative risk (RR) and 95% confidence interval (CI) for each time period and cohort were calculated.Results: There were 767 731 births (3725 stillbirths) in Wales and 648 373 (2431 stillbirths) in WA. The overall stillbirth rate declined by 15.9% over the study period in Wales (from 5.3 in 1993-96 to 4.5 per 1000 births in 2013-15; P trend < .01) but by 40.4% in WA (from 4.9 to 2.9 per 1000 births in WA; P trend < .01). Using 1993-96 in WA as the reference group, the adjusted RRs for stillbirths at 37-38 weeks' gestation in the most recent study period (2013-15) were 0.85 (95% CI 0.64, 1.13) in Wales and 0.51 (95% CI 0.36, 0.73) in WA. Conclusions:The stillbirth rates between Wales and WA have widened in the last two decades (especially among late-term births), although the absolute rates for both are distinctly higher than the best-performing nations. While the differences may be partly explained by timing of birth and maternal life style behaviours such as smoking, it is important to identify and ameliorate the associated risk factors to support a reduction in preventable stillbirths.

Trends in early gestation stillbirths and neonatal deaths in New South Wales, Australia 2002–2019

“…While our study showed declining early gestation stillbirth and neonatal death rates, there are conflicting findings on trends in early gestation stillbirths and neonatal deaths, particularly across gestational age groups. A Western Australian study found no evidence of a trend in the stillbirth rates at 24–27 weeks gestation during 1993–2015, while another reported a declining trend in the stillbirth rates among singleton births at 20–27 weeks in the same state during 1986–2010 7,8 . No change in the neonatal death rate among singletons at <24 weeks gestation was reported during 1988–2017 in Queensland, although rates decreased at 24–27 weeks; however, pregnancy terminations were included in these analyses 17 .…”

“…However, a declining trend in these rates has not been consistently observed across all late gestation age groups . S tatistically significant decreases in the stillbirth rate at 28–31 weeks were reported in Wales during 1993–2015, but not at 32–36, 37–38 and 39–41 weeks 7 . In the United Kingdom, neonatal death rates decreased from 2015 to 2019 at 28–31, 32–36 and 37–41 weeks, but increased at ≥42 weeks 10 .…”

“…Australian studies have reported both increasing and decreasing trends in stillbirth rates among earlier gestational age groups (20-27 weeks), while evidence of no trend has also been found. [7][8][9] Decreasing trends in late gestation (≥28 weeks) stillbirth and neonatal rates have also been reported in Australia, although this trend has not been observed across all late gestation age groups in other countries. 5,7,10 Most research and prevention efforts to date have focused on late gestation (≥28 weeks) perinatal deaths, especially in relation to stillbirths.…”

“…Trends in rates have been reported to differ across gestational age groups revealing inconsistencies, particularly for stillbirth. Australian studies have reported both increasing and decreasing trends in stillbirth rates among earlier gestational age groups (20–27 weeks), while evidence of no trend has also been found 7–9 . Decreasing trends in late gestation (≥28 weeks) stillbirth and neonatal rates have also been reported in Australia, although this trend has not been observed across all late gestation age groups in other countries 5,7,10 …”

Learning from cross‐country differences in stillbirth rates—Where to now?

“…This reflects, in itself, the lack of priority given to stillbirth as a public health problem, but also the paucity of high‐quality routine population birth data in many countries and the complicated politics of defining the lower threshold for viability for recording births and of creating clear registration guidelines for pregnancy terminations, which are commonly registered as stillbirths. In this context, the study by Bailey et al 2 in this issue of Paediatric and Perinatal Epidemiology , which optimises existing data on stillbirths to explore trends and risk factors in countries with similar standards of living and access to health services, is valuable.…”