The association between different aspects of socioeconomic deprivation and severe maternal morbidity.

IntroductionLiving in a deprived neighborhood is associated with an increased risk of severe maternal morbidity (SMM), but the specific deprivation factors or individual SMM conditions driving this risk remain unclear. This study examined how different domains and subdomains of the Index of Multiple Deprivation (IMD) are associated with SMM, identifying key contributors.Material and methodsWe conducted a nationwide, population-based cohort study using English Hospital Episode Statistics Admitted Patient Care (HES APC) data. The cohort included 4 040 106 women aged 10-55 years who gave birth in NHS facilities in England between January 1, 2013, and March 31, 2023, with pregnancies of ≥20 weeks' gestation. Multilevel multivariable Poisson regression estimated adjusted risk ratios (aRR) and 95% confidence intervals (CI) of composite SMM and key individual SMM conditions for each IMD quintile compared to the least deprived quintile, and aRR (95% CI) of composite SMM in each IMD domain/subdomain quintile compared to the least deprived quintile.ResultsIMD domains showed varying associations with SMM. Income and employment deprivation had the strongest associations, with women living in the most deprived quintile having aRRs of 1.16 (95% CI 1.12-1.20) and 1.15 (95% CI 1.11-1.19) compared to those living in the least deprived quintile, respectively. Contrastingly, high geographical barriers to services were associated with a lower risk of SMM (aRR: 0.92 (95% CI 0.88-0.95)). Sepsis, acute cardiac events, and embolism play a key role in the association between composite deprivation and SMM, with women living in the most deprived areas having risk ratios of 1.43 (95% CI 1.36-1.50), 1.24 (95% CI 1.09-1.41), and 1.97 (95% CI 1.69-2.29), respectively, for each of the conditions, compared to women living in the least deprived areas.ConclusionsThere appears to be a widening gap in the risk of SMM between women living in the least and most deprived areas in England, with sepsis, cardiac events, and embolism having the strongest association with deprivation. Composite measures of area-level deprivation may obscure the diverse impacts of specific deprivation factors, and individual-level socioeconomic measures are needed to clarify pathways contributing to SMM risk.