The purpose of this analysis is to evaluate the association between community-level social vulnerability and the incidence of severe maternal morbidity in one academic hospital system. Retrospective analysis of women with non-anomalous singleton or twin gestations identified from a university healthcare system, 2014-2020. Women at high-risk for spontaneous ± medically indicated PTB were included in a 1:2 ratio with low-risk controls. Each woman’s address was geocoded and assigned to a census tract, then linked at the census tract level to the CDC’s Social Vulnerability Index (SVI). The SVI tool integrates 15 census variables to produce composite scores across 4 major domains (socioeconomic, household composition & disability, minority status & language, and housing type & transportation) plus a composite SVI score. Higher SVI scores indicate greater social vulnerability. The primary outcome was SMM (per CDC definition). For this analysis, women who had a blood transfusion but met no other SMM criteria were not considered to have SMM. Data were analyzed by chi-square, t-test, and logistic regression. 50,998 women met inclusion criteria; 453 (0.89%) had SMM. Participant characteristics are shown in Table 1. Women who experienced SMM were significantly more likely to live in an area with higher composite SVI scores (mean 0.49 vs. 0.44, p=0.002) and higher scores in the socioeconomic (0.43 vs. 0.39, p=0.002) and household composition & disability (0.45 vs. 0.41, p<0.001) domains compared to those without SMM. Scores in the minority status & language (0.62 vs. 0.59, p=0.07) and housing type & transportation (0.51 vs. 0.49, p=0.13) domains did not differ by SMM diagnosis. In multivariable logistic regression models, domain 2 (household composition and disability) remained associated with a significantly higher odds of SMM. Though living in an area with higher total social vulnerability during pregnancy was not associated with an increased risk of SMM, women living in census tracts with higher SVI related to household composition and disability were at higher risk for SMM.View Large Image Figure ViewerDownload Hi-res image Download (PPT)