Inequalities in preterm birth by deprivation and ethnicity: A national cohort study in England

Abstract Background Preterm birth has decreased in the UK; however, the extent of inequalities remains unclear. This study aimed to quantify socioeconomic and ethnic inequalities in preterm birth rates using routinely collected maternity data in England. Methods Retrospective analysis of cohort data from the NHS England Hospital Episode Statistics (HES). All women aged 13-55 with a singleton livebirth (April 2018 to March 2021) at 24-42 weeks were included. Multivariate Poisson regression was used to estimate the rate of preterm birth (livebirth between 24 + 0 and 36 + 6 weeks’) for each ethnic and deprivation postcode group, these were compared to white women from the least deprived 20% of areas. We iteratively developed the model, adjusting for covariates associated with preterm birth. A post-hoc calculation identified the rate of preterm birth for each ethnic group at each level of deprivation. Results We identified 1,111,045 livebirths between April 2018 and March 2021. The rate of preterm birth increased with socioeconomic deprivation and was highest at 7.1% per 100 livebirths (95%CI:7.00-7.20) in women living in the 20% most deprived areas, compared to 5.6% (95%CI:5.50-5.74) in women in the 20% least deprived areas. White women had the lowest preterm birth rate at 6.5% (95%CI:6.47-6.58) and South Asian women had the highest rate at 6.9% (95%CI:6.76-7.04) (Table 2). The rate of preterm birth increased according to increased area-level deprivation across all ethnic groups. In areas of high deprivation, the preterm birth rate was similar across ethnic groups. Whereas in less deprived areas, there were marked inequalities between ethnic groups. Conclusions Inequalities in preterm birth remain, despite overall decreases in preterm birth. We found area deprivation and individual ethnicity interact to increase the risk of preterm birth in marginalized communities. Interventions need to holistically consider the structural and socioenvironmental determinants of preterm birth. Key messages • Area deprivation and ethnicity remain key drivers of inequalities in preterm birth, despite overall decreases in preterm birth. • To reduce inequalities tailored prevention strategies are needed to address socioenvironmental and structural determinants of preterm birth in high deprivation areas and minoritized ethnicity groups.