From inequality gradients to priority bands: Translating preterm birth inequalities into targeted universalist policy in England.

Preterm Births (PTBs) are viewed as one of the major causes of neonatal morbidity, mortality and health-system cost in England. The incidence of preterm is persistently greatest among those experiencing socioeconomic and ethnic inequalities. This study aims to quantify deprivation and ethnicity gradients, using the available dataset, in PTBs and subsequently to translate deprivation-related inequality into policy-relevant priority bands. It analyses aggregated live-birth data for England (2020-2021), stratified separately by gestational age × Index of Multiple Deprivation (IMD), and gestational age × maternal ethnicity. Socioeconomic inequalities are summarised using the Slope Index of Inequality (SII), Relative Index of Inequality (RII), deprivation-attributable excess cases, and the population attributable fraction (PAF) with the least deprived quintile as reference. Subsequently, a two-axis rule combining relative risk and share of excess burden is applied to derive the prioritised target bands. The data analysed comprises 1,179,195 live births in 2020-2021, demonstrating a monotonic increment across populations, from 6.39% in the least deprived quintile to 8.71% in the most deprived. The most deprived quintile accounted for 57.7% of deprivation-attributable excess PTBs. Differences across ethnic disparities were also evident, with the highest PTB rate being among Black Caribbeans (10.22%; RR 1.37 vs White British births). Translation of inequalities into deprivation-based priority bands provides an empirical bridge between surveillance and targeted universalist prevention policy, thus supporting proportionate resource allocation in high-burden populations.