Socio-economic and ethnic inequalities in premature birth in England: a retrospective-cohort study of national data.

Problem

Premature birth (<37 weeks) has lifelong health consequences and excessively burdens minorities and those living in high deprivation in the UK. As primary care remains the first line of contact for most mothers regarding their antenatal and reproductive healthcare, services need to be aware of inequalities and contributing factors. In England, the COVID-19 pandemic severely impacted maternal health and access to care, thus premature birth and associated inequalities need to be examined further in this context. This research aimed to identify and quantify the socioeconomic and ethnic inequalities in premature birth rates in England.

Approach

We conducted a retrospective cohort study that used data from the NHS England, Hospital Episode Statistics (HES) database. All women who had a singleton live birth between 1st April 2018 and 31st March 2021 were included. Pregnancies with a gestation period of less than 24 weeks or more than 42 weeks were excluded, as were pregnancies recorded as ectopic, terminated, or aborted. Age was restricted to between 13 and 55 years. Ethnicity groups included White, Mixed, South Asian, Black, and Other. Deprivation was based on the English Index of Multiple Deprivation and aggregated into quintiles ranging from least deprived 20% to the most deprived 80% - 100%. We used multivariate modified Poisson regression and robust standard errors to ascertain the risk of premature birth in each deprivation quintile and ethnicity group. Models were adjusted for the interaction between deprivation and ethnicity, age, year, parity, previous adverse birth outcomes, and maternal health covariates.

Findings

We identified 1,590,902 maternity-related admissions in England recorded in HES. Of these records, 1,111,045 singleton live births with no missing data, were included in complete case analyses. In the fully adjusted model, the risk of preterm birth was 5.32% (95%CI:5.19-5.45). The risk of preterm birth increased with socioeconomic deprivation; the highest deprivation quintile was 1.32 times more likely to give birth preterm than the lowest quintile (95%CI:1.29-1.36). Regarding ethnicity groups, only South Asian ethnicity groups remained at 1.13 times higher risk for preterm birth than white ethnicity groups (95%CI:1.05-1.22). Across all ethnicity groups, increasing deprivation was associated with an increased risk of premature birth. Those who tested positive for COVID-19 were at 1.77 times higher risk of giving birth preterm (95%CI: 1.64-1.91) and the period of tiered lockdown restrictions was associated with a 6% decrease in premature births (95%CI:0.91-0.98).

Consequences

Our findings suggest that deprivation is a considerable risk factor for preterm birth, with the most deprived groups suffering the highest risks of prematurity. Although the impact of deprivation appears to be additive across all ethnicity groups, South Asian ethnicity groups are particularly vulnerable to premature birth. Targeted policies and tailored support structures are warranted to achieve and sustain equity long-term.