Preterm delivery and low birth weight among first-born infants of black and white college graduates

Road to Equity in Maternal and Child Health: Honoring the Past and Blazing New Paths

PURPOSE

This paper is a historical account of an initiative, as recalled by the authors who were directly involved, that brought to the forefront the long-standing and unjust reproductive health inequities in the United States. It is composed of three distinct but interrelated parts that together map the past, present, and future of addressing racial inequities in Maternal and Child Health.

DESCRIPTION

This paper is composed of three distinct but interrelated parts that together map the past, present, and future of addressing racial inequities in Maternal and Child Health. Part I recounts the history and achievements of a Centers for Disease for Control and Prevention initiative in the 1980-90's, led by the Prematurity Research Group in the Division of Reproductive Health, Pregnancy and Infant Health Branch. This initiative stimulated a paradigm shift in how we understand and address black infant mortality and the inequities in this outcome. Part II illustrates examples of some exemplary programmatic and policy legacies that stemmed either directly or indirectly from the Centers for Disease for Control and Prevention paradigm shift. Part III provides a discussion of how effectively the current practice in Maternal and Child Health applies this paradigm to address inequities and proposes a path for accelerating Title V agencies' progress toward birth equity.

ASSESSMENT

This CDC initiative was transformative in that it raised the visibility of African American researchers, moved the field from a focus on traditional epidemiologic risks such as personal health promotion and medical interventions, to include racism as a risk factor for inequitable birth outcomes. The paradigm examined the specific roles of historical and structural racism, and the racialized, contextualized, and temporal exposures that are unique to Black women's experiences in the United States.

CONCLUSION

The initiative radically changed the narratives about the underlying factors contributing to inequities in birth outcomes of Black women, altered the way we currently approach addressing inequities, and holds the keys for transforming practice to a more holistic and systematic approach to building sustained organizational structures in maternal and child health that accelerate the achievement of birth equity.

Association between Sexual Activity during Pregnancy, Pre- and Early-Term Birth, and Vaginal Cytokine Inflammation: A Prospective Study of Black Women

This study aimed to investigate the association between sexual activity during pregnancy and adverse birth outcomes among Black women, and to explore whether vaginal cytokine inflammation mediates this association. Data from 397 Black pregnant women through questionnaires on sexual activity and vaginal biosamples during early (8-14 weeks) and late (24-30 weeks) pregnancy, and birth outcomes were analyzed. Using a data-driven approach, the study found that vaginal sex during late pregnancy was associated with spontaneous early-term birth (sETB, 38-39 completed weeks' gestation) (OR = 0.39, 95% CI: [0.21, 0.72], p-value = 0.003) but not with spontaneous preterm birth (sPTB) (OR = 1.08, p-value = 0.86) compared to full-term birth. Overall, despite vaginal sex in late pregnancy showing an overall positive effect on sETB (total effect = -0.1580, p-value = 0.015), we observed a negative effect of vaginal sex on sETB (indirect effect = 0.0313, p-value = 0.026) due to the fact that having vaginal sex could lead to elevated IL6 levels, which in turn increased the odds of sETB. In conclusion, the study found an overall positive association between sexual activity on ETB and a negative partial mediation effect via increased vaginal cytokine inflammation induced by vaginal sexual activity. This inconsistent mediation model suggested that vaginal sexual activity is a complex behavior that could have both positive and negative effects on the birth outcome.

Using medical expenditure panel survey data to explore the relationship between patient-centered medical homes and racial disparities in severe maternal morbidity outcomes

BACKGROUND

There are persistent racial/ethnic disparities in the occurrence of severe maternal morbidity. Patient-centered medical home care has the potential to address disparities in maternal outcomes.

OBJECTIVES

To examine (1) the association between receiving patient-centered medical home care and severe maternal morbidity outcomes and (2) the interaction of race/ethnicity on patient-centered medical home status and severe maternal morbidity.

DESIGN/METHODS

Using 2007 to 2016 data from the Medical Expenditures Panel Survey, we conducted a cross-sectional study to estimate the association between receipt of care from a patient-centered medical home and the occurrence of severe maternal morbidity, and racial-specific (White, Black, Asian, Other) relative risks of severe maternal morbidity. Our study used race as a proxy measure for exposure racism. We identified mothers (⩾15 years) who gave birth during the study period. We identified patient-centered medical home qualities using 11 Medical Expenditures Panel Survey questions and severe maternal morbidities using medical claims, and calculated generalized estimating equation models to estimate odds ratios of severe maternal morbidity and 95% confidence intervals.

RESULTS

Among all mothers who gave birth (N = 2801; representing 5,362,782 US lives), only 25% received some exposure patient-centered medical home care. Two percent experienced severe maternal morbidity, and this did not differ statistically (p = 0.11) by patient-centered medical home status. However, our findings suggest a 85% decrease in the risk of severe maternal morbidity among mothers who were defined as always attending a patient-centered medical home (odds ratios: 0.15; 95% confidence interval:0.01-1.87; p = 0.14) and no difference in the risk of severe maternal morbidity among mothers who were defined as sometimes attending a patient-centered medical home (odds ratios: 1.00; 95% confidence interval:0.16-6.42; p = 1.00). There was no overall interaction effect in the model between race and patient-centered medical home groups (p = 0.82), or ethnicity and patient-centered medical home groups (p = 0.62) on the severe maternal morbidity outcome.

CONCLUSION

While the rate of severe maternal morbidity was similar to US rates, few mothers received care from a patient-centered medical home which may be due to underreporting. Future research should further investigate the potential for patient-centered medical home-based care to reduce odds of severe maternal morbidity across racial/ethnic groups.

Racial/ethnic disparities in severe maternal morbidity: An intersectional lifecourse approach

Despite long-existing calls to address alarming racial/ethnic gaps in severe maternal morbidity (SMM), research that considers the impact of intersecting social inequities on SMM risk remains scarce. Invoking intersectionality theory, we sought to assess SMM risk at the nexus of racial/ethnic marginalization, weathering, and neighborhood/individual socioeconomic disadvantage. We used birth hospitalization records from California across 20 years (1997-2017, N = 9,806,406) on all live births ≥20 weeks gestation. We estimated adjusted average predicted probabilities of SMM at the combination of levels of race/ethnicity, age, and neighborhood deprivation or individual socioeconomic status (SES). The highest risk of SMM was observed among Black birthing people aged ≥35 years who either resided in the most deprived neighborhoods or had the lowest SES. Black birthing people conceptualized to be better off due to their social standing (aged 20-34 years and living in the least deprived neighborhoods or college graduates) had comparable and at times worse risk than White birthing people conceptualized to be worse off (aged ≥35 years and living in the most deprived neighborhoods or had a high-school degree or less). Our findings highlight the need to explicitly address structural racism as the driver of racial/ethnic health inequities and the imperative to incorporate intersectional approaches.

Neighborhood conditions and birth outcomes: Understanding the role of perceived and extrinsic measures of neighborhood quality

Living in a disadvantaged neighborhood has been associated with adverse birth outcomes. Most prior studies have conceptualized neighborhoods using census boundaries and few have examined the role of neighborhood perceptions, which may better capture the neighborhood environment. In the present study, we examined associations between extrinsic and perceived neighborhood quality measures and adverse birth outcomes.

Methods

Participants resided in the San Francisco Bay Area of California and were enrolled in Chemicals in Our Bodies, a prospective birth cohort (N = 817). The Index of Concentration at the Extremes (ICE) for income, Area Deprivation Index (ADI), and the Urban Displacement Project's measure of gentrification were included as census block group-level extrinsic neighborhood quality measures. Poor perceived neighborhood quality was assessed using an interview questionnaire. Linear regression models were utilized to examine associations between extrinsic and perceived neighborhood quality measures, and gestational age and birthweight for gestational age z-scores. Covariates in adjusted models were chosen via a directed acyclic graph (DAG) and included maternal age, education, and marital status.

Results

In adjusted models, having poor perceived neighborhood quality was associated with higher birthweight z-scores, relative to those who did not perceive their neighborhood as poor quality (β = 0.21, 95% confidence intervals = 0.01, 0.42). Relative to the least disadvantaged tertile, the upper tertile of the ADI was associated with a modest reduction in gestational age (β = -0.35, 95% confidence intervals = -0.67, -0.02).

Conclusions

In the Chemicals in Our Bodies study population, extrinsic and perceived neighborhood quality measures were inconsistently associated with adverse birth outcomes.

Addressing bias and disparities in periviable counseling and care

Addressing bias and disparities in counseling and care requires that we contend with dehumanizing attitudes, stereotypes, and beliefs that our society and profession holds towards people of color, broadly, and Black birthing people in particular. It also necessitates an accounting of the historically informed, racist ideologies that shape present-day implicit biases. These biases operate in a distinctly complex and damaging manner in the context of end-of-life care, which centers around questions related to human pain, suffering, and value. Therefore, this paper aims to trace biases and disparities that operate in periviable care, where end-of-life decisions are made at the very beginning of life. We start from a historical context to situate racist ideologies into present day stereotypes and tropes that dehumanize and disadvantage Black birthing people and Black neonates in perinatal care. Here, we review the literature, address historical incidents and consider their impact on our ability to deliver patient-centered periviable care.

State Policies, Racial Disparities, and Income Support: A Way to Address Infant Outcomes and the Persistent Black-White Gap?

Low birth weight and preterm births vary by state, and Black mothers typically face twice the risk that their white counterparts do. This gap reflects an accumulation of psychosocial and material exposures that include interpersonal racism, differential experience with area-level deprivation such as residential segregation, and other harmful exposures that the authors refer to as "institutional" or "structural" racism. The authors use logistic regression models and a dataset that includes all births from 1994 to 2017 as well as five state policies from this period-Aid to Families with Dependent Children/Temporary Aid for Needy Families, housing assistance, Medicaid, minimum wage, and the earned income tax credit (EITC)-to examine whether these state social policies, designed to provide a financial safety net, are associated with risk reduction of low birth weight and preterm birth to Black and white mothers, and whether variations in state generosity attenuate the racial inequalities in birth outcomes. The authors also examine whether the relationship between state policies and racial inequalities in birth outcomes is moderated by the education level of the mother. We find that the EITC reduces the risk of low birth weight and preterm birth for Black mothers. The impact is much less consistent for white mothers. For both Black and white mothers, the benefits to birth outcomes are larger for mothers with less education.

Perspectives of Doulas of Color on their Role in Alleviating Racial Disparities in Birth Outcomes: A Qualitative Study

INTRODUCTION

The purpose of this study was to explore how doulas of color conceptualize both their work and how their racial and ethnic identities influence their work within the context of racial disparities in birth outcomes in the United States.

METHODS

We conducted semistructured qualitative interviews with doulas of color who had attended at least 3 births as doulas. Participants were recruited from across the United States. The interviews were audio recorded and transcribed verbatim. Qualitative content analysis was used to derive themes from the transcribed interviews.

RESULTS

Interviews were conducted with 8 doulas of color, ranging in age from 21 to 47 from across the United States. All participants were either current college students or had earned a college degree. Although many of the doulas identified as being of more than one racial or ethnic group, nearly all participants identified closely with being Black or African American first, and their other racial groups second. Four major themes emerged: relationship with the medical system, role of identity in the doulas' work, role of class, and divisions within the natural birth movement.

DISCUSSION

The majority of doulas who participated in this study stated that their racial identity strongly influenced their work, particularly when working with women of the same race or ethnicity due to their shared identities. Several participants initially became doulas because of a desire to alleviate disparities in birth outcomes for women of color. This suggests a commitment on the part of the study participants to serving their communities and to bridging the gap between women of color and the health care system. Several participants also noted that they feel alienated by both the health care system and the mainstream natural birth community.

Racial and ethnic disparities in birth Outcomes: A decomposition analysis of contributing factors

This study seeks to quantify and rank the contribution of selected factors to the observed racial/ethnic disparities in low-birth-weight births (LBWBs) and preterm births (PTBs). Based on vital statistics data on births to primiparous women and characteristics of mothers in the State of Nebraska during the period of 2005 to 2014 (n = 93,375), unadjusted and adjusted odds ratios were estimated to examine the association between selected variables and the odds of having LBWBs or PTBs. Fairlie decomposition analysis was performed to quantify the contribution of each selected factor to racial/ethnic differences in LBWB and PTB rates. The prevalence of PTBs was 9.1% among non-Hispanic White (NHW) women, as compared to 12.8% among non-Hispanic Black (NHB) women and 10.6% among Hispanic women. The corresponding prevalence of LBWBs in the three groups were 5.9%, 11.9%, and 7.2%, respectively. The higher educational attainment among NHW women, relative to NHB women accounted for 10% of the observed difference in LBWB rate between the two groups. Health insurance coverage was the second most important factor accounting for the observed disparities in birth outcomes. Addressing socioeconomic disadvantages in NHB and Hispanic women would be important for them to narrow their gaps with NHW women in LBWB and PTB prevalence. More research is needed to identify key factors leading to the disparities in birth outcomes between NHW and NHB women.

Racial inequity in preterm delivery among college-educated women: The role of racism

BACKGROUND

Non-Hispanic Black (NHB) women face a 50% increased risk of delivering preterm compared to non-Hispanic White (NHW) women in the United States. Sociodemographic and pregnancy risk factors do not fully explain this inequity. This inequity exists even among women with a college education, although recent empirical analysis on racial inequities in preterm delivery (PTD) among college-educated women is lacking. Furthermore, the contribution of preconception risk factors to the racial inequity in PTD has not been examined.

OBJECTIVES

To determine whether: (i) there is a NHB-NHW inequity in PTD among college-educated women; (ii) the prevalence of known, measured sociodemographic, pregnancy, and preconception PTD risk factors differs between NHB and NHW college-educated women; (iii) equalising the distribution of risk factors between college-educated NHB and NHW women reduces or eliminates the racial inequity in PTD.

METHODS

We analysed US natality data from 2015 to 2016 among women with a college degree or higher (n = 2 326 512). We calculated frequencies of sociodemographic, pregnancy, and preconception risk factors among all women and separately by race/ethnicity. We used modified Poisson regression models to estimate the association between race/ethnicity and PTD controlling for known, measured sociodemographic, pregnancy, and preconception factors.

RESULTS

The largest percentage point differences in risk factors between NHW and NHB women were observed for marital status, trimester of care initiation, body mass index, and birth interval. Among college-educated women, the unadjusted risk of PTD for NHB women was 1.77 (95% CI 1.74, 1.79) times the risk for NHW women. After controlling for sociodemographic, pregnancy, and preconception factors, this attenuated to RR 1.47 (95% CI 1.45, 1.49).

CONCLUSIONS

A racial inequity in PTD persists among college-educated women. Racism contributes to the NHB-NHW inequity in PTD, in part, through its influence on known sociodemographic, pregnancy, and preconception risk factors for PTD and, in part, through unmeasured pathways.

Association of Mercury Exposure and Maternal Sociodemographics on Birth Outcomes of Indigenous and Tribal Women in Suriname

Information regarding adverse birth outcomes (ABO) of Indigenous and Tribal women living in the remote tropical rainforest of Suriname, where mercury (Hg) use is abundant in artisanal gold mining, is not available. In the context of a health system analysis, we examined the association between Hg exposure, maternal sociodemographics on the ABO of Indigenous and Tribal women living in Suriname’s interior and its capital, Paramaribo. ABO were determined in pregnant women enrolled from December 2016 to July 2019 in the Caribbean Consortium for Environmental and Occupational Health prospective environmental epidemiologic cohort study. Associations were explored using Pearson’s χ²-test and the Mann–Whitney U-test. Among 351 singleton participants, 32% were Indigenous, residing mainly in the interior (86.8%), and 23.1% had ABO. Indigenous participants had higher rates of ABO (29.8% vs. 19.8%) and preterm birth (PTB) (21.2% vs. 12.4%), higher Hg levels, delivered at a younger age, were less educated, and had lower household income compared to Tribal participants. Multivariate logistic regression models revealed that Indigenous participants had higher odds of ABO (OR = 3.60; 95% CI 1.70–7.63) and PTB (OR = 3.43; 95% CI 1.48–7.96) compared with Tribal participants, independent of Hg exposure and age at delivery. These results highlight the importance of effective risk reduction measures in support of Indigenous mothers, families, and communities.

Maternal Depressive Symptoms, Sleep, and Odds of Spontaneous Early Birth: Implications for Racial Inequities in Birth Outcomes

STUDY OBJECTIVES

Delivery prior to full term affects 37% of US births, including ~400,000 preterm births (<37 weeks) and >1,000,000 early term births (37-38 weeks). Approximately 70% of cases of shortened gestation are spontaneous - without medically-indicated cause. Elucidation of modifiable behavioral factors would have considerable clinical impact.

METHODS

This study examined the role of depressive symptoms and sleep quality in predicting the odds of spontaneous shortened gestation among 317 women (135 Black, 182 White) who completed psychosocial assessment in mid-pregnancy.

RESULTS

Adjusting for key covariates, Black women had 1.89 times higher odds of spontaneous shortened gestation compared to White women (OR (95% CI) = 1.89 (1.01, 3.53), p=0.046). Women who reported only poor subjective sleep quality (PSQI > 6) or only elevated depressive symptoms (CES-D ≥ 16) exhibited no statistically significant differences in odds of spontaneous shortened gestation compared to those with neither risk factor. However, women with comorbid poor sleep and depressive symptoms exhibited markedly higher odds of spontaneous shortened gestation than those with neither risk factor [39.2% versus 15.7%, [OR (95% CI) = 2.69 (1.27, 5.70), p = 0.01]. A higher proportion of Black women met criteria for both risk factors (23% of Black women versus 11% of White women; p=0.004), with a lower proportion experiencing neither risk factor (40.7% of Black versus 64.3% of White women; p < 0.001).

CONCLUSIONS

Additive effects of poor subjective sleep quality and depressive symptoms were observed with markedly higher odds of spontaneous shortened gestation among women with both risk factors. Racial inequities in rates of comorbid exposure corresponded with inequities in shortened gestation. Future empirical studies and intervention efforts should consider the interactive effects of these commonly co-morbid exposures.

Vaginal Microbiome Composition in Early Pregnancy and Risk of Spontaneous Preterm and Early Term Birth Among African American Women

Objective

To evaluate the association between the early pregnancy vaginal microbiome and spontaneous preterm birth (sPTB) and early term birth (sETB) among African American women.

Methods

Vaginal samples collected in early pregnancy (8-14 weeks' gestation) from 436 women enrolled in the Emory University African American Vaginal, Oral, and Gut Microbiome in Pregnancy Study underwent 16S rRNA gene sequencing of the V3-V4 region, taxonomic classification, and community state type (CST) assignment. We compared vaginal CST and abundance of taxa for women whose pregnancy ended in sPTB (N = 44) or sETB (N= 84) to those who delivered full term (N = 231).

Results

Nearly half of the women had a vaginal microbiome classified as CST IV (Diverse CST), while one-third had CST III (L. iners dominated) and just 16% had CST I, II, or V (non-iners Lactobacillus dominated). Compared to vaginal CST I, II, or V (non-iners Lactobacillus dominated), both CST III (L. iners dominated) and CST IV (Diverse) were associated with sPTB with an adjusted odds ratio (95% confidence interval) of 4.1 (1.1, infinity) and 7.7 (2.2, infinity), respectively, in multivariate logistic regression. In contrast, no vaginal CST was associated with sETB. The linear decomposition model (LDM) based on amplicon sequence variant (ASV) relative abundance found a significant overall effect of the vaginal microbiome on sPTB (p=0.034) but not sETB (p=0.320), whereas the LDM based on presence/absence of ASV found no overall effect on sPTB (p=0.328) but a significant effect on sETB (p=0.030). In testing for ASV-specific effects, the LDM found that no ASV was significantly associated with sPTB considering either relative abundance or presence/absence data after controlling for multiple comparisons (FDR 10%), although in marginal analysis the relative abundance of Gardnerella vaginalis (p=0.011), non-iners Lactobacillus (p=0.016), and Mobiluncus curtisii (p=0.035) and the presence of Atopobium vaginae (p=0.049), BVAB2 (p=0.024), Dialister microaerophilis (p=0.011), and Prevotella amnii (p=0.044) were associated with sPTB. The LDM identified the higher abundance of 7 ASVs and the presence of 13 ASVs, all commonly residents of the gut, as associated with sETB at FDR < 10%.

Conclusions

In this cohort of African American women, an early pregnancy vaginal CST III or IV was associated with an increased risk of sPTB but not sETB. The relative abundance and presence of distinct taxa within the early pregnancy vaginal microbiome was associated with either sPTB or sETB.

Prenatal Depression: Assessment and Outcomes among Medicaid Participants

This study used bivariate and regression-adjusted analyses of participant-level survey and medical data to investigate prevalence of depression among pregnant Medicaid participants, correlates of depression, and the relationship between depression and pregnancy outcomes. The sample included Medicaid participants with a single gestation and valid depression data who were enrolled in Strong Start for Mothers and Newborns 2, a national preterm birth prevention program, from 2013 to 2017 (N = 37,287; 85% of total enrollment). Depression rates in Strong Start were high (27.5%). Depression was associated with being black; having other children, an unplanned pregnancy, or challenges accessing prenatal care; not having a co-resident spouse or partner; and experiencing intimate partner violence. After these and other risk factors were controlled for, depression remained associated with higher rates of preterm birth. Systematic screening and holistic approaches to prenatal care that address depression and associated risks could help reduce rates of preterm birth and other poor pregnancy outcomes.

Geographic access to critical care obstetrics for women of reproductive age by race and ethnicity

BACKGROUND

The goal of risk-appropriate maternal care is for high-risk pregnant women to receive specialized obstetrical services in facilities equipped with capabilities and staffing to provide care or transfer to facilities with resources available to provide care. In the United States, geographic access to critical care obstetrics varies. It is unknown whether this variation in proximity to critical care obstetrics differs by race, ethnicity, and region.

OBJECTIVE

We examined the geographic access, defined as residence within 50 miles of a facility capable of providing risk-appropriate critical care obstetrics services for women of reproductive age, by distribution of race and ethnicity.

STUDY DESIGN

Descriptive spatial analysis was used to assess geographic distance to critical care obstetrics for women of reproductive age by race and ethnicity. Data were analyzed geographically: nationally, by the Department of Health and Human Services regions, and by all 50 states and the District of Columbia. Dot density analysis was used to visualize geographic distributions of women by residence and critical care obstetrics facilities across the United States. Proximity analysis defined the proportion of women living within an approximate 50-mile radius of facilities. Source data included the 2015 American Community Survey from the United States Census Bureau and the 2015 American Hospital Association Annual Survey.

RESULTS

Geographic access to critical care obstetrics was the greatest for Asian and Pacific Islander women of reproductive age (95.8%), followed by black (93.5%), Hispanic (91.4%), and white women of reproductive age (89.1%). American Indian and Alaska Native women had more limited geographic access (66%) in all regions. Visualization of proximity to critical care obstetrics indicated that facilities were predominantly located in urban areas, which may limit access to women in frontier or rural areas of states including nationally recognized reservations where larger proportions of white women and American Indian and Alaska Native women reside, respectively.

CONCLUSION

Disparities in proximity to critical care obstetrics exist in rural and frontier areas of the United States, which affect white women and American Indian and Alaska Native women, primarily. Examining insurance coverage, interstate hospital referral networks, and transportation barriers may provide further insight into critical care obstetrics accessibility. Further exploring the role of other equity-based measures of access on disparities beyond geography is warranted.

A Multisite Examination of Everyday Discrimination and the Prevalence of Spontaneous Preterm Birth in African American and Latina Women in the United States

OBJECTIVE

African American women have a higher risk of spontaneous preterm birth than White and Latina women. Although Latina women are exposed to similar social determinants of health, they have lower rates of spontaneous preterm birth. One theory for this difference is the maternal stress biological pathway, whereby lifetime stressors, such as racial discrimination, lead to a premature activation of parturition. We investigated the prevalence of self-reported discrimination and its association with the prevalence of spontaneous preterm birth.

STUDY DESIGN

Using data from the Community Child Health Research Network Study, a multisite cohort study from 2008 to 2012, we conducted a cross-sectional analysis of 1,154 African American women and 578 Latina women.

RESULTS

Adjusting for multiple risk factors, African American and Latina women who experienced the highest tertile of discrimination had a higher prevalence of preterm birth compared with those who experienced discrimination less than once per year, adjusted hazard ratio (aHR) = 1.5 (0.7-3.1) and 3.6 (0.9-14.4), respectively.

CONCLUSION

In our cohort, we found a statistically significant association only in the medium discrimination group in Latina women, but we did not find a statistically significant association in African American women. Reduction in experienced discrimination may be an important intervention for reducing adverse pregnancy outcomes.

Association of Summer Heat Waves and the Probability of Preterm Birth in Minnesota: An Exploration of the Intersection of Race and Education

Preterm birth (PTB) is common and has negative impacts on infant health. While some maternal risk factors have been identified, including age under 20 or over 40, substance abuse, low BMI, and racism, less is known about the impact of environmental exposures like high heat. We combined 154,157 records of live births occurring in Minnesota between 2009 and 2015 with hourly weather records collected from the Minneapolis–St. Paul airport. We tested if maternal heat wave exposure (a seven-day period with a mean daily high temp of 37 °C) immediately prior to birth leads to a higher risk of preterm birth. Additional covariates included maternal age, race/ethnicity, educational status, and residence in the seven-county Minneapolis–St. Paul metro area. Pregnant women exposed to a seven-day heat wave of 37 °C or higher experienced a higher relative risk of PTB compared to women who did not experience a heat wave (1.14 risk ratio (RR), 1.0–1.3 95% confidence interval (CI)). The result is robust to controls for a woman’s age, race/ethnicity, educational attainment, place of residence, and year of the birth. Children born to Black women with college degrees who are exposed to heat waves experience a higher relative risk of PTB compared to White women with college degrees in a heat wave (2.97 RR, 1.5–6.1 95% CI). Summer heat waves are associated with higher risk of PTB in late-term pregnancies in Minnesota.

Sleep disturbances and inflammatory gene expression among pregnant women: Differential responses by race

Excessive inflammation in pregnancy predicts adverse birth outcomes, including shortened gestational length and lower birthweight, with African American women at greater risk. As substantial racial disparities in sleep quality, and evidence that African Americans have increased vulnerability for sleep-induced inflammatory dysregulation, sleep may be a critical, modifiable health behavior that contributes to racial disparities in birth outcomes. The present study examined sleep disturbance as a predictor of genome-wide transcriptome profiles of peripheral blood samples from 103 pregnant women (33 African American, 70 white) assessed at 18.7 ± 7.2 weeks gestation. We hypothesized that pregnant women with significant sleep disturbances would have gene expression profiles indicating over-expression of inflammatory pathways, with greater effects among African American compared to white women. Promoter-based bioinformatics analyses of differentially expressed genes indicated greater activation of NF-кB, AP1, and CREB transcription factors among African American women with sleep disturbances (all p < 0.05), and enhanced activation of AP1, but not NF-кB and reduced CREB activity among white women with sleep disturbances (p < 0.05). Differences in glucocorticoid receptor (GR) activity were also observed, in which African American women with sleep disturbances had reduced GR activity (p < 0.05), but white women with sleep disturbances showed a trend for enhanced GR activity (p = 0.11). Similarly, Interferon Response Factor (IRF) activity was reduced in African American women while increased in white women with sleep disturbances (p < 0.05). The current study provides novel evidence for gene expression related to inflammation, glucocorticoids, and anti-viral immunity among pregnant women with sleep disturbances, with differential effects by race. African Americans showed greater breadth and magnitude in these proinflammatory and anti-viral pathways than whites, with divergence in anti-inflammatory glucocorticoid, proinflammatory adrenergic-mediated cAMP, and anti-viral interferon responses. These data elucidate the role of sleep disturbances in intracellular inflammatory and anti-viral immunity in pregnancy and provide a potential target for intervention.

Racial Disparities in Prematurity Persist among Women of High Socioeconomic Status

Objectives

Despite persistent racial disparities in preterm birth (PTB) in the US among non-Hispanic (NH) black women compared to NH white women, it remains controversial whether sociodemographic factors can explain these differences. We sought to evaluate whether disparities in PTB persist among NH black women with high socioeconomic status (SES).

Study Design

We conducted a population-based cohort study of all live births in the US from 2015-2017 using birth certificate data from the National Vital Statistics System. We included singleton, non-anomalous live births among women who were of high SES (defined as having ≥ 16 years of education, private insurance, and not receiving Women, Infants and Children [WIC] benefits) and who identified as NH white, NH black, or 'mixed' NH black and white race. The primary outcome was PTB <37 weeks; secondary outcomes included PTB <34 and <28 weeks. In addition, analyses were repeated considering birthweight <2500g as a surrogate for preterm birth <37 weeks, birthweight <1500g as a surrogate for preterm birth <34 weeks, and birthweight <750g as a surrogate for preterm birth <28 weeks' gestation. Data were analyzed with chi-square, t-test, and logistic regression.

Results

2,170,686 live births met inclusion criteria, with 92.9% NH white, 6.7% NH black, and 0.4% both NH white and black race. Overall, 5.9% delivered <37, 1.3% <34, and 0.3 % <28 weeks. In unadjusted analyses of women with high SES, the PTB rate at each gestational age cutoff was higher for women of 'mixed' NH white and black race, and highest for women who were NH black only compared to women who were NH white only. In regression models we further adjusted for women with insurance and prenatal care their entire pregnancy, maternal race was associated with higher odds of PTB at each GA cutoff, with the highest odds observed at <28 weeks. Finally, in further adjustement analysis including only the 1,934,912 women who received prenatal care in the first trimester, findings were similar. Rates of preterm birth at each gestational age cutoff remained highest for women who identified as non-Hispanic black, intermediate for women identifying as both non-Hispanic black and white race, and lowest for non-Hispanic white women at <37 weeks (9.9% vs. 6.1% vs. 5.5%, respectively; p<0.001), <34 weeks (3.5% vs. 1.5% vs. 1.1%, respectively; p<0.001), and <28 weeks' gestation (1.2% vs. 0.4% vs. 0.2%, respectively, p<0.001).

Conclusions

Even among college-educated women with private insurance who are not receiving WIC, racial disparities in prematurity persist. These national findings are consistent with prior studies that suggest factors other than socio-demographics are important in the underlying pathogenesis of PTB.

Preterm labor is characterized by a high abundance of amniotic fluid prostaglandins in patients with intra-amniotic infection or sterile intra-amniotic inflammation

Objective: To distinguish between prostaglandin and prostamide concentrations in the amniotic fluid of women who had an episode of preterm labor with intact membranes through the utilisation of liquid chromatography-tandem mass spectrometry.Study design: Liquid chromatography-tandem mass spectrometry analysis of amniotic fluid of women with preterm labor and (1) subsequent delivery at term (2) preterm delivery without intra-amniotic inflammation; (3) preterm delivery with sterile intra-amniotic inflammation (interleukin (IL)-6>2.6 ng/mL without detectable microorganisms); and (4) preterm delivery with intra-amniotic infection [IL-6>2.6 ng/mL with detectable microorganisms].Results: (1) amniotic fluid concentrations of PGE₂, PGF_2α, and PGFM were higher in patients with intra-amniotic infection than in those without intra-amniotic inflammation; (2) PGE₂ and PGF_2α concentrations were also greater in patients with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (3) patients with sterile intra-amniotic inflammation had higher amniotic fluid concentrations of PGE₂ and PGFM than those without intra-amniotic inflammation who delivered at term; (4) PGFM concentrations were also greater in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation who delivered preterm; (5) amniotic fluid concentrations of prostamides (PGE₂-EA and PGF_2α-EA) were not different among patients with preterm labor; (6) amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in cases with intra-amniotic inflammation; and (7) the PGE₂:PGE₂-EA and PGF_2α:PGF_2α-EA ratios were higher in patients with intra-amniotic infection compared to those without inflammation.Conclusions: Mass spectrometric analysis of amniotic fluid indicated that amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in women with preterm labor and intra-amniotic infection than in other patients with an episode of preterm labor. Yet, women with intra-amniotic infection had greater amniotic fluid concentrations of PGE₂ and PGF_2α than those with sterile intra-amniotic inflammation, suggesting that these two clinical conditions may be differentiated by using mass spectrometric analysis of amniotic fluid.

Short interpregnancy interval as a risk factor for preterm birth in non-Hispanic Black and White women in California

OBJECTIVE

Short interpregnancy interval (IPI) is associated with adverse pregnancy outcomes, including preterm birth (PTB < 37 weeks GA). We investigated whether short IPI (< 6 months) contributes to the higher PTB frequency among non-Hispanic Blacks (NHB).

STUDY DESIGN

Using a linked birth cohort > 1.5 million California live births, we examined frequencies of short IPI between racial/ethnic groups and estimated risks by multivariable logistic regression for spontaneous PTB. We expanded the study to births 1991-2012 and utilized a "within-mother" approach to permit methodologic inquiry about residual confounding.

RESULTS

NHB women had higher frequency (7.6%) of short IPI than non-Hispanic White (NHW) women (4.4%). Adjusted odds ratios for PTB and short IPI were 1.64 (95% CI 1.54, 1.76) for NHW and 1.49 (1.34, 1.65) for NHB. Using within-mother analysis did not produce substantially different results.

CONCLUSIONS

Short IPI is associated with PTB but does not explain risk disparity between NHWs and NHBs.

Late preterms: are they all the same?

Very preterm infants (VPT) and, especially extreme low gestational age (ELGA) preterms, often on the threshold of viability, make the headlines of both, the scientific as well as the popular press. However, all together they represent between 1 and 2% of all livebirths. Late preterms (LPT) those born between 34/07 and 36/06 weeks, on the other hand, may account for up to 80% of all preterms and for some 5-8% of all births. Although mortality is low they are prone to increasing neonatal morbidities posing a considerable medical, financial and psychosocial burden. In the last years, for many reasons, LPT appear to have increased considerably throughout the western world. But are LPT neonates all the same? In spite of overlapping gestational ages (GA) LPT may behave quite differently depending on circumstances surrounding their pre- and postnatal events. We can identify three different classes of LPT neonates: spontaneous late preterms (SpLPT) born in the absence of previous maternal illnesses and/or pregnancy related disorders; Induced LPT (IdLPT) due to maternal/fetal complications and those babies being born after 34-week gestation from postponed delivery at an earlier GA (PtLPT) - and they are quite different babies, with different behavior, despite a common and same gestational age.

Racial difference in preterm birth and low birthweight: Towards a new hypothesis involving the interaction of 25-hydroxyvitamin D with maternal fat mass

Preterm birth (PB) and low birthweight (LBW) remain a leading cause of infant mortality worldwide. Persistent racial disparities in prevalence rates have been reported, with the highest values observed in Subsaharan Africa and South Asia. In United States, non-Hispanic Black women are more likely to have a premature or low-birth-weight baby. Beyond the speculative debate on factors explaining such racial disparity, the key-question remains about the path from race to birth outcomes. Several hypotheses emerged from the published literature to explain the racial difference in likelihood for PB and LBW. However, the 'Hispanic paradox' remains unexplained. We relied here on published data to hypothesize that the racial disparity in PB/LBW is a consequence to the joint influence of 25-hydroxyvitamin D and fat mass. Beyond its role as a source of 1,25-dihydroxyvitamin D, the 25-hydroxyvitamin D is directly implicated in the fetal growth and the normal completion of pregnancy. Because of its lipophilic property, a large part of 25-hydroxyvitamin D is swiftly trapped into fat mass and the circulating fraction impact the body development during fetal period. We postulate that the positive effect of vitamin D to prevent PB/LBW is less beneficial for women with high fat mass, independent of race. The core problem may be related to bioavailable 25-hydroxyvitamin D, not directly to race.

Pockets of progress amidst persistent racial disparities in low birthweight rates

Racial disparities persist in adverse perinatal outcomes such as preterm birth, low birthweight (LBW), and infant mortality across the U.S. Although pervasive, these disparities are not universal. Some communities have experienced significant improvements in black (or African American) birth outcomes, both in absolute rates and in rate ratios relative to whites. This study assessed county-level progress on trends in black and white LBW rates as an indicator of progress toward more equal birth outcomes for black infants. County-level LBW data were obtained from the 2003 to 2013 U.S. Natality files. Black LBW rates, black-white rate ratios and percent differences over time were calculated. Trend lines were first assessed for significant differences in slope (i.e., converging, diverging, or parallel trend lines). For counties with parallel trend lines, intercepts were tested for statistically significant differences (sustained equality vs. persistent disparities). To assess progress, black LBW rates were compared to white LBW rates, and the trend lines were tested for significant decline. Each county's progress toward black-white equality was ultimately categorized into five possible trend patterns (n = 408): (1) converging LBW rates with reductions in the black LBW rate (decreasing disparities, n = 4, 1%); (2) converging LBW rates due to worsening white LBW rates (n = 5, 1%); (3) diverging LBW rates (increasing disparities, n = 9, 2%); (4) parallel LBW rates (persistent disparities, n = 373, 91%); and (5) overlapping trend lines (sustained equality, n = 18, 4%). Only four counties demonstrated improvement toward equality with decreasing black LBW rates. There is significant county-level variation in progress toward racial equality in adverse birth outcomes such as low birthweight. Still, some communities are demonstrating that more equitable outcomes are possible. Further research is needed in these positive exemplar communities to identify what works in accelerating progress toward more equal birth outcomes.

Racial and ethnic differences in preterm birth: A complex, multifactorial problem

Preterm birth remains the leading cause of morbidity and mortality among nonanomalous neonates, and is a major public health problem. Non-Hispanic black women have a 2-fold greater risk for preterm birth compared with non-Hispanic white race. The reasons for this disparity are poorly understood and cannot be explained solely by sociodemographic factors. Underlying factors including a complex interaction between maternal, paternal, and fetal genetics, epigenetics, the microbiome, and these sociodemographic risk factors likely underlies the differences between racial groups, but these relationships are currently poorly understood. This article reviews the epidemiology of disparities in preterm birth rates and adverse pregnancy outcomes and discuss possible explanations for the racial and ethnic differences, while examining potential solutions to this major public health problem.

Racial/Ethnic Disparities in Morbidity and Mortality for Preterm Neonates Admitted to a Tertiary Neonatal Intensive Care Unit

OBJECTIVE

The objective of this study was to assess whether in-hospital morbidity or mortality differed by race/ethnicity for preterm neonates admitted to the neonatal intensive care unit (NICU).

STUDY DESIGN

In a retrospective cohort study, preterm infants, < 37 weeks, were admitted to the NICU from 1994 to 2009. Exclusions included structural anomalies and aneuploidy. Primary outcome was in-hospital mortality (IHM). Secondary outcomes were respiratory distress syndrome (RDS), interventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), and retinopathy of prematurity (ROP). Sub-analysis of very preterm (VPT) infants, < 28 weeks, was performed. Five racial/ethnic groups (REGs) were compared: White, Black, Hispanic, Asian, and Mixed. Associations were modeled by logistic regression. White neonates (WNs) were the referent group. Unadjusted and adjusted odds ratios and 95% confidence intervals for remaining REGs were reported. p value was significant at 5% for overall tests and at Bonferroni-corrected level < 0.0125 for between-race comparisons with WNs.

RESULTS

Four thousand nine hundred fifty-five preterm neonates were identified; 153 were excluded leaving 4802 for analysis. After controlling covariates that were chosen a priori, there was no difference across REGs for IHM (all between-race comparison p values > 0.0125). There was a significant difference in RDS among Black neonates (BNs) (aOR 0.57, 95% CI 0.45-0.73; p < 0.001) and Hispanic neonates (HNs) (aOR 0.67, 95% CI 0.50-0.89; p = 0.005) compared to WNs. The risk of ROP was significantly different across REGs with HNs having a 70% increase in ROP (aOR 1.70, 95% CI 1.15-2.49; p = 0.008) and Mixed neonates (MNs) experiencing a 55% reduction (aOR 0.45, 95% CI 0.29-0.68; p < 0.001) compared to WNs. There was no difference in IVH or NEC across REGs (all p values > 0.0125). In the VPT cohort sub-analysis, BNs experienced a significant 59% reduction in IHM compared to WNs (BNs aOR 0.41, 95% CI 0.22-0.73; p = 0.003). MNs experienced a 46% reduction in ROP compared to WNs (aOR 0.54, 95% CI 0.35-0.81; p = 0.004). There was no difference in RDS, IVH, or NEC in very preterm infants across REGs (all between comparison p values > 0.0125).

CONCLUSION

In preterm neonates, in-hospital mortality does not significantly differ across racial and ethnic groups. However, in very preterm infants, in-hospital mortality for Black neonates is improved. There are morbidity differences (RDS, ROP) seen among racial/ethnic groups.

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.

Stressors Across the Life-Course and Preterm Delivery: Evidence From a Pregnancy Cohort

Objectives Growing evidence suggests that pre-conception stressors are associated with increased risk of preterm delivery (PTD). Our study assesses stressors in multiple domains at multiple points in the life course (i.e., childhood, adulthood, within 6 months of pregnancy) and their relation to PTD. We also examine heterogeneity of associations by race/ethnicity, PTD timing, and PTD clinical circumstance. Methods We assessed stressors retrospectively via mid-pregnancy questionnaires in the Pregnancy Outcomes and Community Health Study (1998-2004), a Michigan pregnancy cohort (n = 2559). Stressor domains included abuse/witnessing violence (hereafter "abuse"), loss, economic stress, and substance use. We used logistic and multinomial regression for the following outcomes: PTD (<37 weeks' gestation), PTD by timing (≤34 weeks, 35-36 weeks) and PTD by clinical circumstance (medically indicated, spontaneous). Covariates included race/ethnicity, education, parity, and marital status. Results Stressors in the previous 6 months were not associated with PTD. Experiencing abuse during both childhood and adulthood increased adjusted odds of PTD among women of white or other race/ethnicity only (aOR 1.6, 95 % CI 1.1, 2.5). Among all women, abuse in childhood increased odds of late PTD (aOR 1.5, 95 % CI 1.0, 2.2) while abuse in both childhood and adulthood non-significantly increased odds of early PTD (aOR 1.6, 95 % CI 0.9, 2.7). Sexual, but not physical, abuse in both childhood and adulthood increased odds of PTD (aOR 1.9, 95 % CI 1.0, 3.5). Conclusions Experiences of abuse-particularly sexual abuse-across the life-course may be important considerations when assessing PTD risk. Our results motivate future studies of pathways linking abuse and PTD.

Prevalence of preterm, low birthweight, and small for gestational age delivery after breast cancer diagnosis: a population-based study

BACKGROUND

Black-white disparities in breast cancer incidence rates and birth outcomes raise concerns about potential disparities in the reproductive health of premenopausal breast cancer survivors. We examined the prevalence of preterm birth (PTB), low birthweight (LBW), and small for gestational age (SGA) by breast cancer history and effect modification by race.

METHODS

We analyzed linked North Carolina birth records and Central Cancer Registry files from 1990 to 2009 (n = 2,325,229). We used multivariable negative log-binomial regression to calculate prevalence ratios (PRs) and 95% confidence intervals (CIs) for the association between breast cancer history and PTB, LBW, and SGA.

RESULTS

Of 1,912,269 eligible births, 512 births were to mothers with a previous breast cancer diagnosis history. Average age at breast cancer diagnosis was 31.8 years (SD = 4.7). Mean time from diagnosis to delivery was 3.3 years (SD = 2.8). After multivariable adjustment, the PR was 1.67 (95% CI, 1.42-1.97) for PTB, 1.50 (95% CI, 1.23-1.84) for LBW, and 1.30 (95% CI, 1.05-1.61) for SGA comparing women with a breast cancer history to the general population. Among black mothers, the PRs associated with breast cancer history for PTB, LBW, and SGA were 1.31 (95% CI, 1.00-1.72), 1.49 (95% CI, 1.14-1.94), and 1.44 (95% CI, 1.11-1.87), respectively. The corresponding PRs among white mothers were 2.06 (95% CI, 1.67-2.54), 1.53 (95% CI, 1.12-2.08), and 1.10 (95% CI, 0.77-1.58), respectively. The interaction between breast cancer history and race was statistically significant for associations with PTB, but not for LBW or SGA.

CONCLUSIONS

In our data, women with a breast cancer history were at higher risk of delivering a PTB, LBW, or SGA infant, especially if they received chemotherapy or gave birth within 2 years of their breast cancer diagnosis date.

The Microbiome and Complement Activation: A Mechanistic Model for Preterm Birth

Preterm birth (PTB, <37 completed weeks' gestation) is one of the leading obstetrical problems in the United States, affecting approximately one of every nine births. Even more concerning are the persistent racial disparities in PTB, with particularly high rates among African Americans. There are several recognized pathophysiologic pathways to PTB, including infection and/or exaggerated systemic or local inflammation. Intrauterine infection is a causal factor linked to PTB thought to result most commonly from inflammatory processes triggered by microbial invasion of bacteria ascending from the vaginal microbiome. Trials to treat various infections have shown limited efficacy in reducing PTB risk, suggesting that other complex mechanisms, including those associated with inflammation, may be involved in the relationship between microbes, infection, and PTB. The complement system, a key mediator of the inflammatory response, is an innate defense mechanism involved in both normal physiologic processes that occur during pregnancy implantation and processes that promote the elimination of pathogenic microbes. Recent research has demonstrated an association between this system and PTB. The purpose of this article is to present a mechanistic model of inflammation-associated PTB, which hypothesizes a relationship between the microbiome and dysregulation of the complement system. Exploring the relationships between the microbial environment and complement biomarkers may elucidate a potentially modifiable biological pathway to PTB.

Review: Eicosanoids in preterm labor and delivery: Potential roles of exosomes in eicosanoid functions

Preterm delivery is a major obstetric health problem contributing to poor neonatal outcome including low birth weight, respiratory distress syndrome, gastrointestinal, immunologic, central nervous system, hearing, and vision problems. Worldwide, approximately 15 million babies are born prematurely each year. The critical question which remains is how to identify women destined to deliver preterm from those who will achieve a term delivery. Prostaglandins, in all mammals, are important in the parturient process. Increased intrauterine prostaglandin production is associated with labor and in fact prostaglandin E₂ (PGE₂) or analogs are widely used clinically for cervical ripening and labor induction. Measurements of circulating eicosanoids have been problematic because of the rapid and major clearance by the lungs and then kidneys resulting in very low concentrations in plasma. Moreover, since eicosanoids are produced by all mammalian tissues, the sources of the measured eicosanoids are unknown. Our understanding of how cells communicate has undergone a paradigm shift with the recognition of the role of exosomes in intercellular signaling. Recent publications have identified enzymes and products of arachidonic acid metabolism (eicosanoids) within exosomes. This review will explore the potential roles of exosomes in eicosanoid functions that are critical in preterm labor and delivery.

The epidemiology, etiology, and costs of preterm birth

After decades of rising preterm birth rates in the USA and other countries, recent prematurity rates seem to be on the decline. Despite this optimistic trend, preterm birth rates remain higher in the USA, where nearly one in every eight infants is born early, compared to other developed countries. The prevention of preterm birth is considered a public health priority because of the potential to reduce infant and childhood morbidity and mortality related to this condition. Unfortunately, progress has been modest. One of the greatest challenges in studying this outcome is that preterm birth is a complex condition resulting from multiple etiologic pathways. Recently, experts have developed innovative frameworks for classifying and studying preterm birth based on phenotype. These proposed classification systems have only recently been adopted, but a different perspective on a longstanding problem has the potential to lead to new discoveries.

Examining Life-Course Socioeconomic Position, Contextualized Stress, and Depression among Well-Educated African-American Pregnant Women

PURPOSE

This article explores how childhood and adulthood socioeconomic position (SEP) and socioeconomic mobility, as indicators of life-course experiences, impact the relationship between contextualized stress and depression among well-educated, pregnant African-American women.

METHODS

The Jackson, Hogue, Phillips Contextualized Stress Measure and the Beck Depression Inventory were administered to 101 well-educated, pregnant African-American women during their first and second trimesters. Bivariate associations and regression analysis were conducted to assess life-course SEP, mobility, and contextualized stress as predictors of depression. Based on the demographic data for childhood and adult SES, the SEP and mobility variables were created.

RESULTS

Results from χ2 analysis revealed that high contextual stress was significantly associated with no change in mobility, that is, staying the same. Results from regression models found that contextualized stress was the only predictor for depression. Additionally, life-course SEP and mobility did not moderate the relationship between contextualized stress and depression.

CONCLUSIONS

Our findings illuminated the persistence of racial and gendered stress as risk factors for depression among well-educated, pregnant African-American women, regardless of life-course SEP. We offer an explanation as to why African-American women who possess the material and social resources thought to mediate psychosocial and pregnancy risks remain in jeopardy.

Insights into genetic susceptibility in the etiology of spontaneous preterm birth

Preterm birth (PTB; <37 weeks of gestation) is a complex disorder, whose etiology is influenced by a variety of factors. A greater understanding of the biological mechanisms that contribute to PTB will facilitate identification of those at increased risk and may inform new treatments. To accomplish this, it is vital to elucidate the heritability patterns of this condition as well as the environment and lifestyle factors that increase risk for PTB. Identifying individual genes that contribute to the etiology of PTB presents particular challenges, and there has been little agreement among candidate gene and genome-wide studies performed to date. In this review we will evaluate recent genetic studies of spontaneous PTB, discuss common themes among their findings, and suggest approaches for future studies of PTB.

Maternal Microbiome and Pregnancy Outcomes That Impact Infant Health: A Review

The maternal microbiome is recognized as a key determinant of a range of important maternal and child health outcomes, and together with perinatal factors influences the infant microbiome. This article provides a summary review of research investigating (1) the role of the maternal microbiome in pregnancy outcomes known to adversely influence neonatal and infant health, including preterm birth, cardiometabolic complications of pregnancy such as preeclampsia and gestational diabetes, and excessive gestational weight gain; (2) factors with an established link to adverse pregnancy outcomes that are known to influence the composition of the maternal microbiome; and (3) strategies for promoting a healthy maternal microbiome, recognizing that much more research is needed in this area.

DNA methylation provides insight into intergenerational risk for preterm birth in African Americans

African Americans are at increased risk for spontaneous preterm birth (PTB). Though PTB is heritable, genetic studies have not identified variants that account for its intergenerational risk, prompting the hypothesis that epigenetic factors may also contribute. The objective of this study was to evaluate DNA methylation from maternal leukocytes to identify patterns specific to PTB and its intergenerational risk. DNA from peripheral leukocytes from African American women that delivered preterm (24-34 weeks; N = 16) or at term (39-41 weeks; N = 24) was assessed for DNA methylation using the HumanMethylation450 BeadChip. In maternal samples, 17,829 CpG sites associated with PTB, but no CpG site remained associated after correction for multiple comparisons. Examination of paired maternal-fetal samples identified 5,171 CpG sites in which methylation of maternal samples correlated with methylation of her respective fetus (FDR < 0.05). These correlated sites were enriched for association with PTB in maternal leukocytes. The majority of correlated CpG sites could be attributed to one or more genetic variants. They were also significantly more likely to be in genes involved in metabolic, cardiovascular, and immune pathways, suggesting a role for genetic and environmental contributions to PTB risk and chronic disease. The results of this study may provide insight into the factors underlying intergenerational risk for PTB and its consequences.

Beyond the cross-sectional: neighborhood poverty histories and preterm birth

OBJECTIVES

We examined associations between longitudinal neighborhood poverty trajectories and preterm birth (PTB).

METHODS

Using data from the Neighborhood Change Database (1970-2000) and the American Community Survey (2005-2009), we categorized longitudinal trajectories of poverty for California neighborhoods (i.e., census tracts). Birth data included 23 291 singleton California births from the Maternal and Infant Health Assessment (2003-2009). We estimated associations (adjusted for individual-level covariates) between PTB and longitudinal poverty trajectories and compared these to associations using traditional, cross-sectional measures of poverty.

RESULTS

Compared to neighborhoods with long-term low poverty, those with long-term high poverty and those that experienced increasing poverty early in the study period had 41% and 37% increased odds of PTB (95% confidence interval [CI] = 1.18, 1.69 and 1.09, 1.72, respectively). High (compared with low) cross-sectional neighborhood poverty was not associated with PTB (odds ratio = 1.08; 95% CI = 0.91, 1.28).

CONCLUSIONS

Neighborhood poverty histories may contribute to an understanding of perinatal health and should be considered in future research.

Race/ethnicity and the risk of childhood leukaemia: a case-control study in California

BACKGROUND

We conducted a large registry-based study in California to investigate the association between race/ethnicity and childhood leukaemia focusing on two subtypes: acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML).

METHODS

We obtained information on 5788 cases and 5788 controls by linking California cancer and birth registries. We evaluated relative risk of childhood leukaemia by race and ethnicity of the child and their parents using conditional logistic regression, with adjustment for potential confounders.

RESULTS

Compared with Whites, Black children had lower risk of ALL (OR=0.54, 95% CI 0.45 to 0.66) as well as children of Black/Asian parents (OR=0.31, 95% CI 0.10 to 0.94). Asian race was associated with increased risk of AML with OR=1.643, 95% CI 1.10 to 2.46 for Asian vs Whites; and OR=1.67, 95% CI 1.04 to 2.70 for Asian/Asian vs White/White. Hispanic ethnicity was associated with increased risk of ALL (OR=1.37, 95% CI 1.22 to 1.52). A gradient in risk of ALL was observed while comparing Hispanic children with both parents Hispanic, one parent Hispanic and non-Hispanic children (p Value for trend <0.0001). The highest risk of ALL was observed for children with a combination of Hispanic ethnicity and White race compared with non-Hispanic whites (OR=1.27, 95% CI 1.12 to 1.44). The lowest risk was observed for non-Hispanic blacks (OR=0.46, 95% CI 0.36 to 0.60). Associations for total childhood leukaemia were similar to ALL.

CONCLUSIONS

Our results confirm that there are ethnic and racial differences in the incidence of childhood leukaemia. These differences indicate that some genetic and/or environmental/cultural factors are involved in aetiology of childhood leukaemia.

Childbearing Postponement and Child Well-being: A Complex and Varied Relationship?

Over the past several decades, U.S. fertility has followed a trend toward the postponement of motherhood. The socioeconomic causes and consequences of this trend have been the focus of attention in the demographic literature. Given the socioeconomic advantages of those who postpone having children, some authors have argued that the disadvantage experienced by certain groups would be reduced if they postponed their births. The weathering hypothesis literature, by integrating a biosocial perspective, complicates this argument and posits that the costs and benefits of postponement may vary systematically across population subgroups. In particular, the literature on the weathering hypothesis argues that, as a consequence of their unique experiences of racism and disadvantage, African American women may experience a more rapid deterioration of their health which could offset or eventually reverse any socioeconomic benefit of postponement. But because very few African American women postpone motherhood, efforts to find compelling evidence to support the arguments of this perspective rely on a strategy of comparison that is problematic because a potentially selected group of older black mothers are used to represent the costs of postponement. This might explain why the weathering hypothesis has played a rather limited role in the way demographers conceptualize postponement and its consequences for well-being. In order to explore the potential utility of this perspective, we turn our attention to the UK context. Because first-birth fertility schedules are similar for black and white women, we can observe (rather than assume) whether the meaning and consequences of postponement vary across these population subgroups. The results, obtained using linked UK census and birth record data, reveal evidence consistent with the weathering hypothesis in the United Kingdom and lend support to the arguments that the demographic literature would benefit from integrating insights from this biosocial perspective.

The vaginal microbiome, vaginal anti-microbial defence mechanisms and the clinical challenge of reducing infection-related preterm birth

Ascending bacterial infection is implicated in about 40-50% of preterm births. The human vaginal microbiota in most women is dominated by lactobacilli. In women whose vaginal microbiota is not lactobacilli-dominated anti-bacterial defence mechanisms are reduced. The enhanced proliferation of pathogenic bacteria plus degradation of the cervical barrier increase bacterial passage into the endometrium and amniotic cavity and trigger preterm myometrial contractions. Evaluation of protocols to detect the absence of lactobaciili dominance in pregnant women by self-measuring vaginal pH, coupled with measures to promote growth of lactobacilli are novel prevention strategies that may reduce the occurrence of preterm birth in low-resource areas.

Race-based job discrimination, disparities in job control, and their joint effects on health

OBJECTIVES

To examine disparities between job control scores in Black and White subjects and attempt to discern whether self-rated low job control in Blacks may arise from structural segregation into different jobs, or represents individual responses to race-based discrimination in hiring or promotion.

METHODS

Data from the National Survey of Midlife in the United States (MIDUS) were analyzed by mixed-effects linear regression and variance regression to determine the effects of grouping by occupation, and racial discrimination in hiring or promotion, on control scores from the Job Content Questionnaire in Black and White subjects. Path analyses were constructed to determine the mediating effect of discrimination on pathways from education and job control to self-rated health.

RESULTS

Black subjects exhibited lower mean job control scores compared to Whites (mean score difference 2.26, P < 0.001) adjusted for age, sex, education, and income. This difference narrowed to 1.86 when adjusted for clustering by occupation, and was greatly reduced by conditioning on race-based discrimination (score difference 1.03, P = 0.12). Path analyses showed greater reported discrimination in Blacks with increasing education, and a stronger effect of job control on health in Black subjects.

CONCLUSIONS

Individual racially-based discrimination appears a stronger determinant than structural segregation in reduced job control in Black workers, and may contribute to health disparities consequent on work.

Stress-induced inflammatory responses in women: effects of race and pregnancy

OBJECTIVE

African Americans experience preterm birth at nearly twice the rate of whites. Chronic stress associated with minority status is implicated in this disparity. Inflammation is a key biological pathway by which stress may affect birth outcomes. This study examined the effects of race and pregnancy on stress-induced inflammatory responses.

METHODS

Thirty-nine women in the second trimester of pregnancy (19 African American, 20 white) and 39 demographically similar nonpregnant women completed an acute stressor (Trier Social Stress Test). Psychosocial characteristics, health behaviors, and affective responses were assessed. Serum interleukin (IL)-6 was measured at baseline, 45 minutes, and 120 minutes poststressor.

RESULTS

IL-6 responses at 120 minutes poststressor were 46% higher in African Americans versus whites (95% confidence interval = 8%-81%, t(72) = 3.51, p = .001). This effect was present in pregnancy and nonpregnancy. IL-6 responses at 120 minutes poststressor tended to be lower (15%) in pregnant versus nonpregnant women (95% confidence interval = -5%-32%, p = .14). Racial differences in inflammatory responses were not accounted for by demographics, psychological characteristics, health behaviors, or differences in salivary cortisol. Pregnant whites showed lower negative affective responses than did nonpregnant women of either race (p values ≤ .007).

CONCLUSIONS

This study provides novel evidence that stress-induced inflammatory responses are more robust among African American women versus whites during pregnancy and nonpregnancy. The ultimate impact of stress on health is a function of stressor exposure and physiological responses. Individual differences in stress-induced inflammatory responses represent a clear target for continued research efforts in racial disparities in health during pregnancy and nonpregnancy.

Unique variation in genetic selection among Black North American women and its potential influence on pregnancy outcome

We hypothesize that variations in the frequency of genetic polymorphisms, reflecting ancestral differences in living conditions and exposure to microorganisms, increase susceptibility to adverse pregnancy outcome among present day Black North American women. Striking differences were observed in the frequency of genetic variants between Black and White or Hispanic women in 5 genes (IL1RN, MBL2, PPARA, ATG16L1, CIAS1) associated with inflammation and anti-microbial immunity. The CIAS1 and IL1RN polymorphisms were associated with altered interleukin-1β serum levels; the MBL2 polymorphism resulted in a decreased serum mannose-binding lectin concentration. Gene polymorphisms associated with an alteration in innate immunity were most frequent in Black women. This may reflect an evolutionary selection in response to an ancient environment containing a high multitude of microorganisms, and may increase susceptibility of Black women to infection-associated preterm birth in the current North American environment.

Transgenerational Consequences of Racial Discrimination for African American Health

Disparities in African American health remain pervasive and persist transgenerationally. There is a growing consensus that both structural and interpersonal racial discrimination are key mechanisms affecting African American health. The Biopsychosocial Model of Racism as a Stressor posits that the persistent stress of experiencing discrimination take a physical toll on the health of African Americans and is ultimately manifested in the onset of illness. However, the degree to which the health consequences of racism and discrimination can be passed down from one generation to the next is an important avenue of exploration. In this review, we discuss and link literature across disciplines demonstrating the harmful impact of racism on African American physical health and the health of their offspring.

Biracial couples and adverse birth outcomes: a systematic review and meta-analyses

BACKGROUND

Differences in birth outcomes such as low birthweight (LBW), preterm births (PTB), stillbirth, differences in birthweight in Black vs. White race are well known. Infants born to biracial parents (mother and father from either Black or White races) also experience higher adverse birth outcomes.

OBJECTIVE

To systematically review and meta-analyze birth outcomes among parents of mixed racial background compared to parents of same race.

SEARCH STRATEGY

Medline, Embase, CINAHL and bibliographies of identified articles were searched for English language studies.

SELECTION CRITERIA

Studies reporting association between parental mixed racial status and LBW, PTB, or small-for-gestational age (SGA) outcomes were included. DATA COLLECTION AND ANALYSES: After exclusion of duplicate cohorts in different publications, data from White mother-Black father (WMBF), Black mother-White father (BMWF) and Black mother-Black father (BMBF) groups were compared with the White mother-White father (WMWF) group.

RESULTS

Eight English language studies from of 26 335 596 singleton births were included and reviewed. Compared to the WMWF group, the adjusted odds ratio (95% confidence intervals) were: (a) low birthweight; 1.21 (1.10-1.33) for WMBF, 1.75(1.64-1.87) for BMWF, and 2.08 (1.81-2.38) for BMBF; (b) preterm births; 1.17 (1.05-1.31) for WMBF, 1.37 (1.18-1.59) for BMWF, and 1.78 (1.59-2.00) for BMBF; and (c) stillbirths; 1.43 (0.92-2.21) for WMBF, 1.51 (1.09-2.08) for BMWF, and 1.85 (1.47-2.32) for BMBF.

CONCLUSION

Biracial status of parents was associated with higher risk for adverse pregnancy outcomes than both White parents but lower than both Black parents, with maternal race having a greater influence than paternal race on pregnancy outcomes.

Epidemiology of late and moderate preterm birth

Preterm birth affects 12.5% of all births in the USA. Infants of Black mothers are disproportionately affected, with 1.5 times the risk of preterm birth and 3.4 times the risk of preterm-related mortality. The preterm birth rate has increased by 33% in the last 25 years, almost entirely due to the rise in late preterm births (34-36 weeks' gestation). Recently attention has been given to uncovering the often subtle morbidity and mortality risks associated with moderate (32-33 weeks' gestation) and late preterm delivery, including respiratory, infectious, and neurocognitive complications and infant mortality. This section summarizes the epidemiology of moderate and late preterm birth, case definitions, risk factors, recent trends, and the emerging body of knowledge of morbidity and mortality associated with moderate and late preterm birth.