Association between socioeconomic disadvantage and severe maternal morbidity and mortality in high-income countries: a systematic review.

BACKGROUND: Socioeconomic position (SEP) is among the most important determinants of variations in health outcomes. This systematic review aimed to summarise the association between socioeconomic disadvantage and the risk of severe maternal morbidity (SMM) and maternal mortality (MM) across high-income countries. METHODS: A comprehensive search was conducted in the MEDLINE, EMBASE, CINAHL and PsycInfo databases and Google Scholar from January 2000 to June 2023. Peer-reviewed papers from observational studies conducted in Organisation for Economic Co-operation and Development countries were included. Meta-analyses of comparable studies, a narrative summary and a harvest plot were undertaken.The risk of bias was assessed using a modified Newcastle-Ottawa tool. RESULTS: The final review included 52 papers. In the meta-analyses, compared with the least amount of neighbourhood deprivation, neighbourhood income, neighbourhood poverty and years of education, the ORs for SMM in the highest group were 1.45 (95% CI 1.13 to 1.85), 1.48 (95% CI 1.34 to 1.63), 1.61 (95% CI 0.97 to 2.66) and 1.29 (95% CI 1.22 to 1.37), respectively. Similarly, the ORs for MM among least versus highest amount of neighbourhood deprivation, unemployed versus employed, lower versus higher occupational group and years of education were 2.10 (95% CI 1.57 to 2.81), 1.86 (95% CI 0.95 to 3.66), 1.61 (95% CI 1.03 to 2.51) and 1.90 (95% CI 1.29 to 2.79), respectively. DISCUSSION: In high-income countries across the different measures of SEP, socioeconomic disadvantage is associated with increased risk for SMM and MM. There is a need for interventions across multiple societal levels that will be effective in reducing these inequitable outcomes. PROSPERO REGISTRATION NUMBER: CRD42023399267.