Improving, but could do better: Trends in gestation-specific stillbirth in Australia, 1994-2015

Abstract

Background: Stillbirth remains a public health concern in high-income countries. Over the past 20 years, stillbirth rates globally have shown little improvement and large disparities. The overall stillbirth rate, which measures risk among births at all gestations, masks diverging trends at different gestations. This study investigates trends over time in gestation-specific risk of stillbirth in Australia.

Methods: Analytical epidemiological study using nationally reported gestational age data for births in Australia, 1994-2015. Average annual change in gestation-specific prospective risk of stillbirth (per 1000 fetuses at risk [FAR]) was calculated among births in 1994-2009 and 2010-2015 at term (37-41 weeks) and for preterm gestational age subgroups: 28-36, 24-27, and 20-23 weeks.

Results: The decline in risk of stillbirth at term from 2010 to 2015 from 1.43 to 1.16 per 1000 FAR was more rapid than from 1994 to 2009; for preterm gestations from 24 to 27 weeks, there were no discernible trends; from 28 to 36 weeks, the decline between 1994 and 2009 was not sustained; among births from 20 to 23 weeks, the risk of stillbirth plateaued in 2010-2015, fluctuating around 3.3 per 1000 FAR.

Conclusions: Improvement in the stillbirth rate from 28 weeks' gestation aligns with changes in other high-income countries, but more work is needed in Australia to achieve the levels of reduction seen elsewhere. Gestation-specific risk of stillbirth is more informative than the overall stillbirth rate. The message that the overall risk of stillbirth is not changing disregards gains at different stages of pregnancy.

Keywords: Australia; fetus at risk; gestation-specific; mortality; stillbirth; trends.