African immigrants' favorable preterm birth rates challenge genetic etiology of the Black-White disparity in preterm birth.

Background: We examined over a million California birth records for 2010 through 2021 to investigate whether disparities in preterm birth (PTB) by nativity and race support the widely held but hitherto unsubstantiated belief that genetic differences explain the persistent Black-White disparity in PTB. Methods: We examined PTB rates and risk ratios among African-, Caribbean-, and U.S.-born Black women compared to U.S.-born White women. Multivariate analyses adjusted for maternal age, education, number of live births, delivery payer, trimester of prenatal care initiation, pre-pregnancy BMI, smoking, and prevalence of poverty in a woman's residence census tract; and for paternal education. Results: In adjusted analyses, African-born Black women's PTB rates were no different from those of U.S.-born White women. Discussion: The results add to prior evidence making a genetic etiology for the racial disparity in PTB unlikely. If genetic differences tied to "race" explained the Black-White disparity in PTB among U.S.-born women, the African immigrants in this study would have had higher rates of PTB, not the lower rates observed. Multiple explanations for the observed patterns and their implications are discussed. Failure to distinguish causes of PTB from causes of the racial disparity in PTB have likely contributed to erroneous attribution of the racial disparity to genetic differences. Based on the literature, unmeasured experiences of racism, including racism-related stress and adverse environmental exposures, are plausible explanations for the PTB disparity between Black and White U.S.-born women. The favorable birth outcomes of African-born Black immigrants may reflect less exposure to racism during sensitive life periods, e.g., childhood, when they were in African countries, where Black people are in the racial majority.

Explaining the Black-White Disparity in Preterm Birth: A Consensus Statement From a Multi-Disciplinary Scientific Work Group Convened by the March of Dimes.

In 2017-2019, the March of Dimes convened a workgroup with biomedical, clinical, and epidemiologic expertise to review knowledge of the causes of the persistent Black-White disparity in preterm birth (PTB). Multiple databases were searched to identify hypothesized causes examined in peer-reviewed literature, 33 hypothesized causes were reviewed for whether they plausibly affect PTB and either occur more/less frequently and/or have a larger/smaller effect size among Black women vs. White women. While definitive proof is lacking for most potential causes, most are biologically plausible. No single downstream or midstream factor explains the disparity or its social patterning, however, many likely play limited roles, e.g., while genetic factors likely contribute to PTB, they explain at most a small fraction of the disparity. Research links most hypothesized midstream causes, including socioeconomic factors and stress, with the disparity through their influence on the hypothesized downstream factors. Socioeconomic factors alone cannot explain the disparity's social patterning. Chronic stress could affect PTB through neuroendocrine and immune mechanisms leading to inflammation and immune dysfunction, stress could alter a woman's microbiota, immune response to infection, chronic disease risks, and behaviors, and trigger epigenetic changes influencing PTB risk. As an upstream factor, racism in multiple forms has repeatedly been linked with the plausible midstream/downstream factors, including socioeconomic disadvantage, stress, and toxic exposures. Racism is the only factor identified that directly or indirectly could explain the racial disparities in the plausible midstream/downstream causes and the observed social patterning. Historical and contemporary systemic racism can explain the racial disparities in socioeconomic opportunities that differentially expose African Americans to lifelong financial stress and associated health-harming conditions. Segregation places Black women in stressful surroundings and exposes them to environmental hazards. Race-based discriminatory treatment is a pervasive stressor for Black women of all socioeconomic levels, considering both incidents and the constant vigilance needed to prepare oneself for potential incidents. Racism is a highly plausible, major upstream contributor to the Black-White disparity in PTB through multiple pathways and biological mechanisms. While much is unknown, existing knowledge and core values (equity, justice) support addressing racism in efforts to eliminate the racial disparity in PTB.

A Prematurity Collaborative Birth Equity Consensus Statement for Mothers and Babies.

INTRODUCTION: In 2016, March of Dimes (MOD) launched its Prematurity Collaborative to engage a broad cross section of national experts to address persistent and widening racial disparities in preterm birth by achieving equity and demonstrated improvements in preterm birth. African-American and Native American women continue to have disproportionate rates of preterm birth and maternal death. As part of the Collaborative, MOD created the Health Equity Workgroup whose task was the creation of a scientific consensus statement articulating core values and a call to action to achieve equity in preterm birth utilizing health equity and social determinants of health frameworks. METHODS: Health Equity Workgroup members engaged in-person and virtually to discuss key determinant contributors and resolutions for disparate maternal and birth outcomes. Workgroup members then drafted the Birth Equity Consensus Statement that contained value statements and a call to action. The birth equity consensus statement was presented at professional conferences to seek broader support. This article highlights the background and context towards arriving at the core values and call to action, which are the two major components of the consensus statement and presents the core values and call to action themselves. RESULTS: The result was the creation of a birth equity consensus statement that highlights risks and protections of social determinants based on the prevailing science, and identifies promising solutions for reducing preterm birth and eliminating racial disparities. CONCLUSION: The birth equity consensus statement provides a mandate, guiding the work of March of Dimes and the broader MCH community, for equity-based research, practice, and policy advocacy at local, state, and federal levels. SIGNIFICANCE: This field report adds to the current knowledge base on racial and ethnic disparities in birth and maternal health outcomes. Research has documented the science behind eliminating health disparities. Scientists and practitioners should continue to explore in practice how the social determinants of birth and maternal health, which manifest historically and contemporarily, can be addressed.

Worry about racial discrimination: A missing piece of the puzzle of Black-White disparities in preterm birth?

OBJECTIVES: The causes of the large and persistent Black-White disparity in preterm birth (PTB) are unknown. It is biologically plausible that chronic stress across a woman's life course could be a contributor. Prior research suggests that chronic worry about experiencing racial discrimination could affect PTB through neuroendocrine, vascular, or immune mechanisms involved in both responses to stress and the initiation of labor. This study aimed to examine the role of chronic worry about racial discrimination in Black-White disparities in PTB. METHODS: The data source was cross-sectional California statewide-representative surveys of 2,201 Black and 8,122 White, non-Latino, U.S.-born postpartum women with singleton live births during 2011-2014. Chronic worry about racial discrimination (chronic worry) was defined as responses of "very often" or "somewhat often" (vs. "not very often" or "never") to the question: "Overall during your life until now, how often have you worried that you might be treated or viewed unfairly because of your race or ethnic group?" Prevalence ratios (PRs) with 95% Confidence Intervals (CI) were calculated from sequential logistic regression models, before and after adjustment for multiple social/demographic, behavioral, and medical factors, to estimate the magnitude of: (a) PTB risks associated with chronic worry among Black women and among White women; and (b) Black-White disparities in PTB, before and after adjustment for chronic worry. RESULTS: Among Black and White women respectively, 36.9 (95% CI 32.9-40.9) % and 5.5 (95% CI 4.5-6.5) % reported chronic worry about racial discrimination; rates were highest among Black women of higher income and education levels. Chronic worry was significantly associated with PTB among Black women before (PR 1.73, 95% CI 1.12-2.67) and after (PR 2.00, 95% CI 1.33-3.01) adjustment for covariates. The unadjusted Black-White disparity in PTB (PR 1.59, 95%CI 1.21-2.09) appeared attenuated and became non-significant after adjustment for chronic worry (PR 1.30, 95% CI 0.93-1.81); it appeared further attenuated after adding the covariates (PR 1.17, 95% CI 0.85-1.63). CONCLUSIONS: Chronic worry about racial discrimination may play an important role in Black-White disparities in PTB and may help explain the puzzling and repeatedly observed greater PTB disparities among more socioeconomically-advantaged women. Although the single measure of experiences of racial discrimination used in this study precluded examination of the role of other experiences of racial discrimination, such as overt incidents, it is likely that our findings reflect an association between one or more experiences of racial discrimination and PTB. Further research should examine a range of experiences of racial discrimination, including not only chronic worry but other psychological and emotional states and both subtle and overt incidents as well. These dramatic results from a large statewide-representative study add to a growing-but not widely known-literature linking racism-related stress with physical health in general, and shed light on the links between racism-related stress and PTB specifically. Without being causally definitive, this study's findings should stimulate further research and heighten awareness of the potential role of unmeasured social variables, such as diverse experiences of racial discrimination, in racial disparities in health.

The role of socioeconomic factors in Black-White disparities in preterm birth.

OBJECTIVES: We investigated the role of socioeconomic factors in Black-White disparities in preterm birth (PTB). METHODS: We used the population-based California Maternal and Infant Health Assessment survey and birth certificate data on 10 400 US-born Black and White California residents who gave birth during 2003 to 2010 to examine rates and relative likelihoods of PTB among Black versus White women, with adjustment for multiple socioeconomic factors and covariables. RESULTS: Greater socioeconomic advantage was generally associated with lower PTB rates among White but not Black women. There were no significant Black-White disparities within the most socioeconomically disadvantaged subgroups; Black-White disparities were seen only within more advantaged subgroups. CONCLUSIONS: Socioeconomic factors play an important but complex role in PTB disparities. The absence of Black-White disparities in PTB within certain socioeconomic subgroups, alongside substantial disparities within others, suggests that social factors moderate the disparity. Further research should explore social factors suggested by the literature-including life course socioeconomic experiences and racism-related stress, and the biological pathways through which they operate-as potential contributors to PTB among Black and White women with different levels of social advantage.

Lifetime racism and blood pressure changes during pregnancy: implications for fetal growth.

OBJECTIVE: Research suggests that exposure to racism partially explains why African American women are 2 to 3 times more likely to deliver low birth weight and preterm infants. However, the physiological pathways by which racism exerts these effects are unclear. This study examined how lifetime exposure to racism, in combination with maternal blood pressure changes during pregnancy, was associated with fetal growth. METHODS: African American pregnant women (n = 39) reported exposure to childhood and adulthood racism in several life domains (e.g., at school, at work), which were experienced directly or indirectly, meaning vicariously experienced when someone close to them was treated unfairly. A research nurse measured maternal blood pressure at 18 to 20 and 30 to 32 weeks gestation. Standardized questionnaires and trained interviewers assessed maternal demographics. Neonatal length of gestation and birth weight data were collected from medical charts. RESULTS: Childhood racism interacted with diastolic blood pressure to predict birth weight. Specifically, women with two or more domains of indirect exposure to racism in childhood and increases in diastolic blood pressure between 18 and 32 weeks had lower gestational age adjusted birth weight than the other women. A similar pattern was found for direct exposure to racism in childhood. CONCLUSIONS: Increases in diastolic blood pressure between the second and third trimesters predicted lower birth weight, but only when racism exposure in childhood (direct or indirect) was relatively high. Understanding pregnant African American women's lifetime direct and indirect experiences with racism in combination with prenatal blood pressure may improve identification of highest risk subgroups within this population.

Maternal familism predicts birthweight and asthma symptoms three years later.

There are marked ethnic and socioeconomic differences in birthweight and childhood asthma, conditions which may be linked causally or via a third variable. Cultural resources are often credited with diminished health disparities in infancy and childhood among subsets of poor and minority populations; yet direct empirical tests of this hypothesis are needed. In this study, ethnicity, lifespan family socioeconomic position (FSEP), and the cultural resource of familism were compared as predictors of birthweight and expression of asthma symptoms (AE) by age three. Familism and lifespan FSEP were assessed in 4633 socioeconomically disadvantaged African Americans, White Americans, and Latinas upon giving birth, as was offspring birthweight. AE was assessed in offspring through age three. Asthma diagnosis by age three was likelier in very low (≤ 1500 g) and low (≤ 2500 g) birthweight infants compared to infants born at average (2501-3999 g) or larger (≥ 4000 g) birthweights. Asthma risk associated with lower birthweight was higher for Latinos (17-35%) and African Americans (19-23%) than for White Americans (13-14%). As predicted, maternal familism was higher among White Americans than among African Americans and Latinas, an effect that was largely driven by ethnic disparities in lifespan FSEP. Familism predicted continuous birthweight (p = .003) and AE (p = .001) by age three independently of ethnicity and lifespan FSEP accounting for appropriate control variables, including maternal biomedical risk, maternal acculturation, parental marital status, and infant sex. There was a 71-g gain in birthweight for every one-unit increase in familism. The protective effect of familism on AE by age three was strongest for participants of lower lifespan FSEP. Maternal familism is one cultural resource that may reduce reproductive and intergenerational health disparities in both U.S.- and foreign-born Americans. Consistent with our previous work, familism and other nonmaterial resources covary with material resources. Nevertheless, culture is distinguishable from lifespan FSEP and ethnicity, and has health implications beyond associations to ethnicity, lifespan FSEP, and related biomedical and sociodemographic factors.

Adverse birth outcomes in African American women: the social context of persistent reproductive disadvantage.

African Americans have the highest rates of infant mortality and adverse birth outcomes of all major racial/ethnic groups in the United States. The long-standing nature of this disparity suggests the need to shift epidemiologic focus from individual-level risk factors to the larger social forces that shape disease risk in populations. In this article, the African American reproductive disadvantage is discussed within the context of American race relations. The review of the literature focuses on racism as a social determinant of race-based disparities in adverse birth outcomes with specific attention to the viability of genetic explanations, the role of socioeconomic factors, the multidimensional nature of racism, and the stress-induced physiologic pathways by which racism may negatively affect pregnancy. Implications for social work research and practice also are discussed.

Communalism predicts prenatal affect, stress, and physiology better than ethnicity and socioeconomic status.

The authors examined the relevance of communalism, operationalized as a cultural orientation emphasizing interdependence, to maternal prenatal emotional health and physiology and distinguished its effects from those of ethnicity and childhood and adult socioeconomic status (SES). African American and European American women (N = 297) were recruited early in pregnancy and followed through 32 weeks gestation using interviews and medical chart review. Overall, African American women and women of lower socioeconomic backgrounds had higher levels of negative affect, stress, and blood pressure, but these ethnic and socioeconomic disparities were not observed among women higher in communalism. Hierarchical multivariate regression analyses showed that communalism was a more robust predictor of prenatal emotional health than ethnicity, childhood SES, and adult SES. Communalism also interacted with ethnicity and SES, resulting in lower blood pressure during pregnancy for African American women and women who experienced socioeconomic disadvantage over the life course. The effects of communalism on prenatal affect, stress, and physiology were not explained by depressive symptoms at study entry, perceived availability of social support, self-esteem, optimism, mastery, nor pregnancy-specific factors, including whether the pregnancy was planned, whether the pregnancy was desired after conception, or how frequently the woman felt happy to be pregnant. This suggests that a communal cultural orientation benefits maternal prenatal emotional health and physiology over and above its links to better understood personal and social resources in addition to economic resources. Implications of culture as a determinant of maternal prenatal health and well-being and an important lens for examining ethnic and socioeconomic inequalities in health are discussed.

Differences in the self-reported racism experiences of US-born and foreign-born Black pregnant women.

Differential exposure to minority status stressors may help explain differences in United States (US)-born and foreign-born Black women's birth outcomes. We explored self-reports of racism recorded in a survey of 185 US-born and 114 foreign-born Black pregnant women enrolled in Project Viva, a prospective cohort study of pregnant women in Boston, Massachusetts, USA. Self-reported prevalence of personal racism and group racism was significantly higher among US-born than foreign-born Black pregnant women, with US-born women having 4.1 and 7.8 times the odds, respectively, of childhood exposure. In multivariate analyses, US-born women's personal and group racism exposure also was more pervasive across the eight life domains we queried. Examined by immigrant subgroups, US-born women were more similar in their self-reports of racism to foreign-born women who moved to the US before age 18 than to women who immigrated after age 18. Moreover, US-born women more closely resembled foreign-born women from the Caribbean than those from Africa. Differential exposure to self-reported racism over the life course may be a critically important factor that distinguishes US-born Black women from their foreign-born counterparts.

"It's the skin you're in": African-American women talk about their experiences of racism. an exploratory study to develop measures of racism for birth outcome studies.

OBJECTIVES: Stress due to experiences of racism could contribute to African-American women's adverse birth outcomes, but systematic efforts to measure relevant experiences among childbearing women have been limited. We explored the racism experiences of childbearing African-American women to inform subsequent development of improved measures for birth outcomes research. METHODS: Six focus groups were conducted with a total of 40 socioeconomically diverse African-American women of childbearing age in four northern California cities. RESULTS: Women reported experiencing racism (1) throughout the lifecourse, with childhood experiences seeming particularly salient and to have especially enduring effects (2) directly and vicariously, particularly in relation to their children; (3) in interpersonal, institutional, and internalized forms; (4) across different life domains; (5) with active and passive responses; and (6) with pervasive vigilance, anticipating threats to themselves and their children. CONCLUSIONS: This exploratory study's findings support the need for measures reflecting the complexity of childbearing African-American women's racism experiences. In addition to discrete, interpersonal experiences across multiple domains and active/passive responses, which have been measured, birth outcomes research should also measure women's childhood experiences and their potentially enduring impact, perceptions of institutionalized racism and internalized negative stereotypes, vicarious experiences related to their children, vigilance in anticipating future racism events, as well as the pervasiveness and chronicity of racism exposure, all of which could be sources of ongoing stress with potentially serious implications for birth outcomes. Measures of racism addressing these issues should be developed and formally tested.

Race, racism, and racial disparities in adverse birth outcomes.

While the biologic authenticity of race remains a contentious issue, the social significance of race is indisputable. The chronic stress of racism and the social inequality it engenders may be underlying social determinants of persistent racial disparities in health, including infant mortality, preterm delivery, and low birth weight. This article describes the problem of racial disparities in adverse birth outcomes; outlines the multidimensional nature of racism and the pathways by which it may adversely affect health; and discusses the implications for clinical practice.

Racial differences in birth outcomes: the role of general, pregnancy, and racism stress.

OBJECTIVE: This study examined the role of psychosocial stress in racial differences in birth outcomes. DESIGN: Maternal health, sociodemographic factors, and 3 forms of stress (general stress, pregnancy stress, and perceived racism) were assessed prospectively in a sample of 51 African American and 73 non-Hispanic White pregnant women. MAIN OUTCOME MEASURES: The outcomes of interest were birth weight and gestational age at delivery. Only predictive models of birth weight were tested as the groups did not differ significantly in gestational age. RESULTS: Perceived racism and indicators of general stress were correlated with birth weight and tested in regression analyses. In the sample as a whole, lifetime and childhood indicators of perceived racism predicted birth weight and attenuated racial differences, independent of medical and sociodemographic control variables. Models within each race group showed that perceived racism was a significant predictor of birth weight in African Americans, but not in non-Hispanic Whites. CONCLUSIONS: These findings provide further evidence that racism may play an important role in birth outcome disparities, and they are among the first to indicate the significance of psychosocial factors that occur early in the life course for these specific health outcomes.

Stress and blood pressure during pregnancy: racial differences and associations with birthweight.

OBJECTIVE: To extend findings that African American women report greater stress during pregnancy, have higher blood pressure (BP), and are twice as likely to have low birthweight infants relative to white women. This study examines a) racial differences in associations between stress and BP during pregnancy, and b) the combined effects of stress and BP on infant birthweight in a sample of 170 African American and white women. METHODS: A prospective, longitudinal study of pregnant women was conducted in which measures of BP, stress, and other relevant variables were collected. Multiple measures of systolic and diastolic BP were taken at each of three points during pregnancy (18-20, 24-26, and 30-32 weeks gestation). RESULTS: Both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were positively associated with stress in pregnant African American women and not in pregnant white women. In analyses of birthweight, there were no main effects of BP or stress. However, a significant interaction demonstrated that, when stress was high, DBP was negatively associated with birthweight and a combination of high stress and high DBP predicted the lowest birthweight in the sample. Furthermore, African American women were twice as likely as white women to have a combination of high stress and high DBP. CONCLUSIONS: Racial differences in relationships between stress and BP, and the interactive effect of stress and DBP on birthweight together suggest that a high stress-high BP profile may pose a risk for lower birthweight among African American women, in particular, and possibly for all pregnant women.

Stress in African American pregnancies: testing the roles of various stress concepts in prediction of birth outcomes.

BACKGROUND: The persistently higher rates of adverse birth outcomes among African American women are a major public health concern. PURPOSE: The purpose of this study was to explore the relations among psychosocial stress, socioeconomic status, and birth outcomes in African American women. METHODS: A prospective survey research design was used to measure stress exposure, subjective responses to stressors, including intrusive effects of life events, and medical and sociodemographic variables in a sample of 178 pregnant African American women. Birth outcomes were obtained from medical charts. RESULTS: Life event exposure was high, but levels of perceived stress and negative emotional responses were low to moderate. Lower income African American women reported significantly greater pregnancy undesirability than higher income African American women. Educational attainment was not related to any of the stress variables, and neither income nor educational attainment was significantly related to birth outcomes. Number of stressful life events significantly predicted 3% additional variance in gestational age after controlling for potential confounders. Psychosocial stress variables altogether accounted for 7% additional variance in gestational age-adjusted birth weight, with event distress and intrusive thoughts concerning severe life events emerging as the significant independent stress predictors. CONCLUSIONS: These results contribute to our understanding of the complex etiological processes involved in African American birth outcomes and set the stage for further research into their reproductive health status.