Do race and ethnicity modify the association between prepregnancy and prenatal stressful life events and adverse birth outcomes among a population-based sample of at-risk women?

BACKGROUND

Stressful events during pregnancy are recognized risk factors for adverse birth outcomes, including preterm birth (PTB) and small-for-gestational-age (SGA) infant. Prior studies report mixed findings, often due to small samples, limited stress categorization, and inadequate adjustment for confounders. This study addresses these gaps using a large, nationally representative sample to examine associations between partner-related, traumatic, financial, and emotional stress and PTB and SGA and to assess potential effect modification by race/ethnicity.

OBJECTIVES

To evaluate associations between prenatal stressful life events and PTB and SGA among U.S. women (n=177,113; representing 9.6 million births) participating in the Pregnancy Risk Assessment Monitoring System (2016-2021).

STUDY

DESIGN

Cross-sectional analysis using national PRAMs data, a population-based surveillance system that employs stratified random sampling of recent mothers from state birth certificate files. Participants were surveyed 2-6 months postpartum about experiences before, during, and after pregnancy; responses were linked to birth records. Thirteen prenatal life stressors were assessed using self-reported PRAMS survey items. Weighted Poisson regression accounted for the complex sampling design to estimate adjusted prevalence ratios (aPR) for partner-related, traumatic, financial, and emotional stress, controlling for key confounders. Effect modification by race/ethnicity was assessed using interaction terms.

RESULTS

The prevalence of SGA and PTB was 9.5% and 9.1%, respectively. Additionally, 58% of participants experienced at least one of the thirteen life stressors. After adjustment for maternal age, race/ethnicity, maternal education, marital status, and prepregnancy BMI, we found a 6% (95% CI: 0%-10%) and 5% (95% CI: 0%-10%) higher prevalence of SGA for traumatic and financial stress, respectively; and a 7% (95% CI: 3%-12%) and 6% (95% CI: 1%-10%) higher prevalence of PTB for financial stress and emotional stress, respectively. While Hispanic ethnicity or non-White race was associated with a higher prevalence of PTB or SGA, stratification by race/ethnicity showed no effect modification (Wald tests, P>.10).

CONCLUSIONS

We identified that traumatic and financial stressors were associated with increased 5% to 6% higher prevalence of SGA, while financial and emotional stressors were associated with a 6% to 7% higher prevalence of PTB in a nationally representative sample. Race and ethnicity did not modify these associations, but persistent disparities highlight the need for targeted interventions. Future research should incorporate prospective designs, measures of perceived stress, and biomarkers to clarify mechanisms and inform strategies to reduce stress-related risks for mothers and infants. VIDEO ABSTRACT.