Stressor landscapes, birth weight, and prematurity at the intersection of race and income: Elucidating birth contexts through patterned life events

Abstract

Women of color and women in poverty experience disproportionately high rates of adverse birth outcomes in the United States (US). We use an intersectionality-based approach to examine how maternal life events (LE's) preceding childbirth are patterned and shape birth outcomes at the intersection of race and income. Using population data from the Pregnancy Risk Assessment Monitoring System we uncover common maternal LE clusters preceding births in 2011-2015, offering a description and measurement of what we call "stressor landscapes" that go beyond standard measures by frequency or type alone. Three landscapes emerge: (1) Protected, characterized by very few LE's; (2) Illness/Isolated, with very few LE's and most commonly involving an illness or death of someone close; and (3) Toxic/Cumulative, comprising more frequent and acute LE's. Mothers in the toxic landscape experience on average 107-g lighter birth weights and a 27%, 49%, and 57% greater risk of PTB, LBW, and VLBW, respectively, compared to in the protected landscape. Low-income and non-Hispanic black (NHB), Hispanic, American Indian (AI), and Alaska Native (AN) mothers are among the groups disproportionately exposed to toxic stressor landscapes. The association between landscape and birth outcomes additionally varies by race and income. Among non-Hispanic white mothers, toxic landscapes are linked to poor birth outcomes at lower incomes. Among NHB mothers, illness-related stressors are additionally linked to worse outcomes and stressor landscapes disproportionately harm middle-income mothers. Toxic stressors may contribute to worse outcomes among middle- and high-income Hispanic and AI/AN mothers, but these patterns are less clear. Our study offers a new approach to measuring LE's that match common conceptions of exposure clustering and applies it to US population data to reveal LE patterns underlying persistent social disparities in maternal and child health.

Keywords: Birth weight; Intersectionality theory; Life events; Preterm birth; Racial inequities; Social epidemiology; Social stress; USA.

Fig. 1

Percentages of mothers experiencing individual LE's overall and within each stressor landscape (unweighted [n] and weighted [N] counts listed). Percentages are weighted based on the PRAMS design to represent US resident live births during 2011 through 2015 from 32 participating states and New York City.

Fig. 2

Probability of being born in toxic stressor landscape (TSL) based on maternal race/ethnicity and income, adjusting for age, education, marital status, and state of residence. Estimations were derived using marginal standardization and based on US resident live births during 2011 through 2015 from 32 participating states and New York City, calculated using CDC survey weights.

Fig. 3

Birth outcome margins by race, income, and stressor landscape: (A) birth weight (continuous) and (B) risk of adverse birth outcomes (preterm birth, low birth weight, and very low birth weight). Each model controls for maternal age, parity, height, BMI, education, marital status at birth, and state of residence; and includes all interaction terms between race, income, and stressor landscapes.