Due to improvements in sanitation and nutrition, adoption of family planning, and advancements in healthcare, the UK experienced large reductions in infant mortality rates (IMR) during the late 1800s and much of the 1900s [1, 2]. Since the 1990s, however, trends have been less encouraging. From 1990 onwards the UK’s downward IMR trajectory flattened and fell behind that of other high-income countries, with projections estimating that by 2030 the UK’s IMR could be 80% higher than the median rate of comparable countries [3]. More recently, an unusual 4-year consecutive rise in IMR in England was observed between 2014–2017 and whilst this trend was subsequently attributed to increasing numbers of early neonatal deaths of infants born at < 24+ 0 weeks gestation, improvements in IMR after exclusion of these events still appeared to be slowing, with annual decreases of 0.14 and 0.04 per 1000 live births before and after 2014, respectively. Persistent socio-economic inequalities in IMR are also a cause for concern, with infants from the most deprived areas in England having a 94% higher risk of death compared to infants from the least deprived areas [4].
Although causal relationships have not been confirmed, the UK’s socio-economic environment has been cited as contributing to the recent trends in IMR and socio-economic inequalities. Following the 2008 global financial crisis the UK Government introduced an austerity programme in 2010, which has made significant changes to the UK’s tax and benefit systems, and to public spending. Concerns have been raised that these reforms have had a disproportionately negative impact upon the most deprived infants in the UK [5]. For example, the two-child benefit limit which was introduced in 2017 has resulted in low-income families who have a third or subsequent child losing entitlement to additional support that equates to £2,780 per child per year. Evaluating the impact of this policy, the Scottish Government predicted that 20,000 households would drop into relative poverty after housing costs. [6]. The impact of austerity on mortality and socio-economic inequalities have also been postulated to extend beyond the early years, with studies hypothesising that austerity may be contributing to the observation of stalling and in some instances worsening life expectancy in high-income countries. [7]
The impact that early life health can have on later life course outcomes, and hence wider population health and health inequalities, is widely recognised [8, 9]. It is therefore vital that trends in child health outcomes are examined, using robust indicators such as IMR, so that policy makers are aware of potential impacts that social and fiscal policies have on early life health and that the need for interventions to improve early life health can be recognised early.
In Scotland, the most recent analysis of IMR by socio-economic position (SEP) was conducted between 1981–2011. This study showed downward trends in early neonatal, late neonatal, and post-neonatal mortality rates across all SEP groups but reported persistent socio-economic inequalities. During the study period absolute inequality remained stable amongst early neonates, increased for late-neonates, and declined amongst post-neonates [10]. However, as the study concluded in 2011, it could not capture the impact of austerity.
In the context of concerning trends elsewhere in the UK, and with a strong policy focus on early life health in Scotland, this study aimed to investigate trends in IMR by SEP in Scotland, between 2000–2018 and examine if there was a change in absolute or relative inequality before and after the introduction of austerity in 2010. As the most common causes of death vary by age at death, we also analysed trends in the sub-groups of neonatal mortality (infant deaths at 0–27 days of life) and post-neonatal mortality (infant deaths at 28 days to < 1 year of life). Additionally, as stillbirths, which are defined as infants delivered at or beyond 24+ 0 weeks gestation who do not breathe or show any other signs of life, are closely related to and can enhance the understanding of trends in IMR, we incorporated these into analysis using the extended perinatal mortality rate, which measures neonatal deaths and stillbirths per 1000 (live and still) births.