Socioeconomic inequalities in neonatal mortality are observed globally but gaps remain in the evidence from current reviews, specifically: a wider range of socioeconomic indicators at the individual, household and area level than previous reviews, and alternative time frames to define neonatal mortality. Thus, a comprehensive updated review of the literature is required, focusing on multiple measures of socioeconomic status and alternative time frames, to assess the relationship between maternal socioeconomic status and neonatal mortality in high-income countries.

Three different search approaches will be used: electronic searching of three databases, grey literature searching and reference list checking. First, the three databases Medline, Scopus and Web of Science will be searched using relevant synonyms and adapted terms from medical subject heading terms (MeSH) in Medline for maternal socioeconomic status and neonatal mortality identified from previous systematic reviews on inequalities in adverse pregnancy outcomes. Second, grey literature will be searched by entering the relevant terms into Google. Title, abstract and full text screening will be conducted by the review team against the inclusion and exclusion criteria, with at least 10% checked by a second reviewer to assess for any bias and errors. We will also conduct the kappa statistic for inter-rater reliability. Third, the reference lists of included studies will be reviewed for any additional studies that meet the criteria. Data will be extracted using a data extraction form and extracted studies will be assessed using the Liverpool Quality Assessment Tool. A narrative synthesis will be conducted and, where appropriate, meta-analysis will be performed. If the data allow, subgroup analysis by neonatal care population and specific gestational ages will be performed.

Ethical approval is not required as all studies in this systematic review will be publicly available. The findings of this review will be presented at conferences and disseminated in peer-reviewed publications.

CRD42022315407.