Fetal death and neighborhood socioeconomic disadvantage

Abstract

OBJECTIVE: Fetal death affects 1 in 175 pregnancies annually in the United States, representing 21,105 fetal deaths in 2021. 1,2 Recent studies emphasize individual social determinants of health (SDOH) as risk factors for fetal death, including Medicaid health insurance, inadequate prenatal care, and living in poverty. 3,4 Neighborhood-level SDOH, such as the area deprivation index (ADI), are associated with adverse pregnancy outcomes; 5 however, whether an association exists with fetal death remains to be clarifi ed. The ADI, available at www.neighborhoodatlas. medicine.wisc.edu, is composed of 17 education, employment, housing-quality, and poverty measures updated using census data. In this study, our aim was to evaluate the association between neighborhood socioeconomic disadvantage and fetal death. STUDY DESIGN: This secondary analysis is from the prospective cohort Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-To-Be study. Residential addresses in the first trimester were geocoded and linked to the 2015 ADI at the census tract level. The ADI was analyzed intertiles as follows: tertile 1 (T1), least disadvantaged as the reference; and T3, most disadvantaged. The outcome was fetal death, de fi ned as intrauterine fetal demise at >= 20 weeks. Modified Poisson regression with robust error variance was used for the analysis and incorporated individual-level covariates based on a directed acyclic graph (Supplemental Figure 1). We also assessed whether the above association varied by self-reported race and ethnicity because of persistent disparities in the risk of stillbirth by race and ethnicity. RESULTS: Of 10,038 individuals, the analytic sample included 9588 individuals (Supplemental Figure 2 and Supplemental Table 1). The median ADI was 39 (interquartile range [IQR], 18 - 71), and sociodemographic and clinical characteristics differed by ADI tertile (Supplemental Table 2). A total of 47 individuals experienced a fetal death (38 antepartum and 9 intrapartum) identified at a median gestational age of 26 weeks (IQR, 21 - 36); none had major anomalies. The frequency of fetal death increased with greater neighborhood deprivation, from 4 per 1000 individuals in T1 to 9 per 1000 individuals in T3 ( P < .01). Individuals living in the most disadvantaged neighborhoods (T3) were more likely to experience a fetal death compared to those living in the least disadvantaged neighborhoods (T1) (adjusted risk ratio, 2.15; 95% confidence interval, 1.03 - 4.48) (Table). The association between ADI and fetal death was similar regardless of race and ethnicity (interaction P = .90). CONCLUSION: In this birth cohort of nulliparous individuals, those who lived in the most disadvantaged US neighborhoods were at increased risk of fetal death. In a population-level case-control study from England, individuals living with the most socioeconomic deprivation were more likely to experience a fetal death. 2 A recent crosssectional study using the US National Inpatient Sample found that fetal deaths were higher among individuals who experienced individual-level adverse SDOH. 3 A previous study from the current cohort found that lower educational attainment, government insurance, and low household income were each associated with an increased risk of fetal death. 4 The limitations of this study include the assessment of ADI at a single time early during pregnancy, and the inclusion of only nulliparous individuals at tertiary care centers, thereby potentially limiting generalizability.The strengths of this study include a prospective design and a large, diverse, multicenter US cohort. Most data regarding stillbirth are from administrative databases or case-control studies.