(932) Association between Social Vulnerability Index and Adverse Pregnancy Outcomes

Objective:
To examine the association between the social vulnerability index (SVI) and adverse pregnancy outcomes, including maternal mortality.

Study Design:
This was a cross-sectional study of county-level data analysis of individuals who delivered in the United States from 2016 to 2021. The study population includes individuals aged 10-44 at the time of delivery who gave live births, stillbirths, or suffered maternal death. The SVI ranges 0-1, with 1 being the highest vulnerability. Counties were categorized based on the SVI quartile (Q1 < 25^th percentile, Q2 25-49^th percentile, Q3 50-74^th percentile, Q4 75^th or greater). Our primary outcome was maternal mortality, defined as “the death of a woman while pregnant or within 42 days of termination of pregnancy.” Secondary outcomes included maternal mortality up to one year postpartum, stillbirth, and preterm birth < 37 weeks. We conducted Bayesian spatial models with Conditional Autoregressive Priors to calculate log relative risk (RR) with 95% confidence intervals (95%CI), which considered spatial autocorrelation.

Results:
Of 22,667,460 births, there were 6,731 maternal mortalities, 9,702 mortalities up to one year postpartum, 275,884 stillbirths, 2,285,797 preterm births, and 7,225,076 cesarean deliveries from 3,012 counties. Maternal mortality rate (MMR) per 100,000 births and SVI categories are shown in Figure 1. As the SVI increases, incidences of maternal mortality increase (Q1 22.8; Q2 25.7; Q3 31.1; and Q4 34.5 per 100,000 births) (Table 1). Higher SVI groups had increased risks of maternal mortality (Q2 RR 1.10, 95%CI 0.99-1.22; Q3 RR 1.27, 95%CI RR 1.15-1.41; Q4 RR 1.54, 95%CI 1.39-1.72). Higher SVI groups also had increased risks of other adverse pregnancy outcomes (Table 1).

Conclusion:
High SVI is associated with an increased risk of adverse pregnancy outcomes. The SVI could be used to identify counties that need policies to address health disparities.