Preterm birth among African American and white women: a multilevel analysis of socioeconomic characteristics and cigarette smoking

Depression at the intersection of race/ethnicity, sex/gender, and sexual orientation in a nationally representative sample of US adults: a design-weighted intersectional MAIHDA

This study examined how race/ethnicity, sex/gender, and sexual orientation intersect under interlocking systems of oppression to socially pattern depression among US adults. With cross-sectional data from the 2015-2020 National Survey on Drug Use and Health (n = 234 722), we conducted a design-weighted, multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA) under an intersectional framework to predict past-year and lifetime major depressive episodes (MDEs). With 42 intersectional groups constructed from 7 race/ethnicity, 2 sex/gender, and 3 sexual orientation categories, we estimated age-standardized prevalence and excess or reduced prevalence attributable to 2-way or higher interaction effects. Models revealed heterogeneity across groups, with prevalence ranging from 1.9% to 19.7% (past-year) and 4.5% to 36.5% (lifetime). Approximately 12.7% (past year) and 12.5% (lifetime) of total individual variance was attributable to between-group differences, indicating key relevance of intersectional groups in describing the population distribution of depression. Main effects indicated, on average, that people who were White, women, gay/lesbian, or bisexual had greater odds of MDE. Main effects explained most between-group variance. Interaction effects (past year: 10.1%; lifetime: 16.5%) indicated another source of heterogeneity around main effects average values, with some groups experiencing excess or reduced prevalence compared with main effects expectations. We extend the MAIHDA framework to calculate nationally representative estimates from complex sample survey data using design-weighted, Bayesian methods. This article is part of a Special Collection on Mental Health.

Clinical, Sociodemographic, and Neighborhood Characteristics Associated with Adverse Pregnancy Outcomes

Background: Cardiovascular risk is increased by a history of adverse pregnancy outcomes (APOs). Efforts to understand and prevent these adverse outcomes may improve both fetal and birthing persons' outcomes in the peripartum period, and over the patient's lifetime. This study aims to assess the association of clinical, sociodemographic, and economic neighbor-hood factors with preterm birth (PTB) and APOs (the composite of stillbirth, small for gestation age, and low birthweight). Materials and Methods: This is a cross-sectional study using the electronic medical records of deliveries from seven Northwell Health hospitals between January 1, 2018 and July 31, 2020. There were 62,787 deliveries reviewed in this study. Deliveries that were not the first for the patient during the study period and multiple gestational pregnancies were excluded. Patients with incomplete data on outcome were also excluded. Main outcomes were PTB and composite APOs. Measures included history of PTB, hypertension, diabetes, body mass index, race/ethnicity, age, preferred language, marital status, parity, health insurance, and median income, percent unemployment, and mean household size by zip code. Results: Of the 62,787 deliveries, 43.3% were from white, Non-Hispanic, and Non-Latino patients. There were 4,552 (7.2%) PTBs and 8,634 (13.8%) APOs. Patients enrolled in public insurance had higher odds of PTB (odds ratio [OR] 1.15, 95% CI 1.06-1.24) and APOs (OR 1.19, 95% CI 1.12-1.25). There was a statistically significant association of both PTB (p = 0.037) and APOs (p = 0.005) when comparing patients that live in a zip code with a median income over 100k to those with an income <100k. In addition, living in a zip code within the second quintile of unemployment was associated with lower odds of APOs (OR 0.92, 95% CI 0.84-0.99). Conclusions: Numerous sociodemographic and clinical factors are associated with both PTB and APOs. Tailored programs addressing these disparities may improve outcomes in pregnant persons.

Neighborhood Walkability as a Risk Factor for Preterm Birth Phenotypes in Two Philadelphia Hospitals from 2013-2016

A total of one in ten infants is born preterm in the U.S. with large racial disparities. Recent data suggest that neighborhood exposures may play a role. Walkability-how easily individuals can walk to amenities-may encourage physical activity. We hypothesized that walkability would be associated with a decreased risk of preterm birth (PTB) and that associations would vary by PTB phenotype. PTB can be spontaneous (sPTB) from conditions such as preterm labor and preterm premature rupture of membranes, or medically indicated (mPTB) from conditions such as poor fetal growth and preeclampsia. We analyzed associations of neighborhood walkability (quantified by their Walk Score® ranking) with sPTB and mPTB in a Philadelphia birth cohort (n = 19,203). Given racial residential segregation, we also examined associations in race-stratified models. Walkability (per 10 points of Walk Score ranking) was associated with decreased odds of mPTB (aOR 0.90, 95% CI: 0.83, 0.98), but not sPTB (aOR 1.04, 95% CI: 0.97, 1.12). Walkability was not protective for mPTB for all patients; there was a non-significant protective effect for White (aOR 0.87, 95% CI: 0.75, 1.01), but not Black patients (aOR 1.05, 95% CI: 0.92, 1.21) (interaction p = 0.03). Measuring health effects of neighborhood characteristics across populations is key for urban planning efforts focused on health equity.

Use of high-resolution metabolomics to assess the biological perturbations associated with maternal exposure to Bisphenol A and Bisphenol F among pregnant African American women

BACKGROUND

Human and animal exposure to bisphenol A (BPA) has been associated with adverse developmental and reproductive effects. The molecular mechanisms by which BPA exposure exerts its effects are not well-understood, even less known about its analogues bisphenol F (BPF). To address these knowledge gaps, we conducted an untargeted metabolome-wide association study (MWAS) to identify metabolic perturbations associated with BPA/BPF exposures in a pregnant African American cohort.

METHODS

From a subset of study participants enrolled in the Atlanta African American Maternal-Child cohort, we collected both urine samples, for targeted exposure assessment of BPA (N = 230) and BPF (N = 48), and serum samples, for high-resolution metabolomics (HRM) profiling (N = 230), during early pregnancy (8-14 weeks' gestation). Using an established untargeted HRM workflow consisting of MWAS modeling, pathway enrichment analysis, and chemical annotation and confirmation, we investigated the potential metabolic pathways and features associated with BPA/BPF exposures.

RESULTS

The geometric mean creatinine-adjusted concentrations of urinary BPA and BPF were 0.85 ± 2.58 and 0.70 ± 4.71 µg/g creatinine, respectively. After false positive discovery rate correction at 20 % level, 264 and 733 unique metabolic features were significantly associated with urinary BPA and BPF concentrations, representing 10 and 12 metabolic pathways, respectively. Three metabolic pathways, including steroid hormones biosynthesis, lysine and lipoate metabolism, were significantly associated with both BPA and BPF exposure. Using chemical standards, we have confirmed the chemical identity of 16 metabolites significantly associated with BPA or BPF exposure.

CONCLUSIONS

Our findings support that exposure to BPA and BPF in pregnant women is associated with the perturbation of aromatic amino acid metabolism, xenobiotics metabolism, steroid biosynthesis, and other amino acid metabolism closely linked to stress responses, inflammation, neural development, reproduction, and weight regulation.

Pregnancy anxiety, placental corticotropin-releasing hormone and length of gestation

OBJECTIVE

High pregnancy anxiety is a consistent predictor of earlier labor and delivery. Placental corticotropin-releasing hormone (pCRH) predicts earlier delivery consistently and it has been identified as a biological mediator of the association between pregnancy anxiety and gestational length. However, studies have not examined whether changes in pregnancy anxiety are associated with earlier birth as mediated by changes in pCRH during pregnancy. Accordingly, this study tests whether linear changes in pregnancy anxiety are associated with length of gestation indirectly through nonlinear increases in pCRH over pregnancy.

METHODS

A sample of pregnant women (n=233) completed prenatal assessments in early pregnancy, second trimester, and third trimester that included a 4-item assessment of pregnancy anxiety and collection of blood samples assayed for pCRH using radioimmunoassay. Length of gestation was abstracted from medical records after birth.

RESULTS

Increases in pregnancy anxiety from early pregnancy to third trimester predicted shorted length of gestation, as did nonlinear increases in pCRH over pregnancy. However, there was no evidence of an indirect effect of changes in pregnancy anxiety on length of gestation via changes in pCRH.

CONCLUSIONS

These results indicate that linear changes in pregnancy anxiety and nonlinear changes in pCRH during pregnancy are independent risk factors for shortened gestational length. This study adds to a small but growing body of work on biopsychological processes in pregnancy and length of gestation. Modeling changes in psychological and biological processes during pregnancy could provide more insight into understanding risk for adverse pregnancy outcomes.

Mediators of socioeconomic inequalities in preterm birth: a systematic review

BACKGROUND

Rates of preterm birth are substantial with significant inequalities. Understanding the role of risk factors on the pathway from maternal socioeconomic status (SES) to preterm birth can help inform interventions and policy. This study therefore aimed to identify mediators of the relationship between maternal SES and preterm birth, assess the strength of evidence, and evaluate the quality of methods used to assess mediation.

METHODS

Using Scopus, Medline OVID, "Medline In Process & Other Non-Indexed Citation", PsycINFO, and Social Science Citation Index (via Web of Science), search terms combined variations on mediation, socioeconomic status, and preterm birth. Citation and advanced Google searches supplemented this. Inclusion criteria guided screening and selection of observational studies Jan-2000 to July-2020. The metric extracted was the proportion of socioeconomic inequality in preterm birth explained by each mediator (e.g. 'proportion eliminated'). Included studies were narratively synthesised.

RESULTS

Of 22 studies included, over one-half used cohort design. Most studies had potential measurement bias for mediators, and only two studies fully adjusted for key confounders. Eighteen studies found significant socioeconomic inequalities in preterm birth. Studies assessed six groups of potential mediators: maternal smoking; maternal mental health; maternal physical health (including body mass index (BMI)); maternal lifestyle (including alcohol consumption); healthcare; and working and environmental conditions. There was high confidence of smoking during pregnancy (most frequently examined mediator) and maternal physical health mediating inequalities in preterm birth. Significant residual inequalities frequently remained. Difference-of-coefficients between models was the most common mediation analysis approach, only six studies assessed exposure-mediator interaction, and only two considered causal assumptions.

CONCLUSIONS

The substantial socioeconomic inequalities in preterm birth are only partly explained by six groups of mediators that have been studied, particularly maternal smoking in pregnancy. There is, however, a large residual direct effect of SES evident in most studies. Despite the mediation analysis approaches used limiting our ability to make causal inference, these findings highlight potential ways of intervening to reduce such inequalities. A focus on modifiable socioeconomic determinants, such as reducing poverty and educational inequality, is probably necessary to address inequalities in preterm birth, alongside action on mediating pathways.

Differences in Psychosocial Protective Factors by Race/Ethnicity and Socioeconomic Status and Their Relationship to Preterm Delivery

Background: Non-Hispanic Black (“Black”) women in the United States deliver preterm at persistently higher rates than non-Hispanic White (“White”) women, and disparities in preterm delivery (PTD) also exist by socioeconomic factors. Research is needed to identify and understand factors that are protective against PTD for Black women and low socioeconomic status (SES) women.

Methods: We examined seven potential protective factors at the individual, interpersonal, and neighborhood levels during pregnancy to determine if they (1) differed in prevalence by race/ethnicity and SES and (2) were associated with risk of PTD overall or within specific race/ethnicity and SES groups. We used prospectively collected data from n = 2474 women who were enrolled in the Pregnancy Outcomes and Community Health Study conducted in Michigan (1998–2004).

Results: White women reported higher levels of self-esteem, mastery, perceived social support, instrumental social support, and reciprocity compared to Black women (all p < 0.01), while Black women reported higher levels of religiosity compared to white women (p < 0.01). High SES women reported higher levels of all protective factors compared to middle and low SES women (all p < 0.01). While protective factors were not independently associated with PTD, religiosity was associated with lower odds of PTD among low SES women (OR 0.6, 95% CI 0.4-0.9) and among Black women (OR 0.6, 95% CI 0.4–1.0), respectively.

Conclusions: Our findings highlight the importance of assessing how protective factors may operate differently across race/ethnicity and SES to promote healthy pregnancy outcomes. Future studies should examine mechanisms that elucidate potential causal pathways between religiosity and PTD for Black women and low SES women.

High-resolution metabolomics of exposure to tobacco smoke during pregnancy and adverse birth outcomes in the Atlanta African American maternal-child cohort

Exposure to tobacco smoke during pregnancy has been associated with a series of adverse reproductive outcomes; however, the underlying molecular mechanisms are not well-established. We conducted an untargeted metabolome-wide association study to identify the metabolic perturbations and molecular mechanisms underlying the association between cotinine, a widely used biomarker of tobacco exposure, and adverse birth outcomes. We collected early and late pregnancy urine samples for cotinine measurement and serum samples for high-resolution metabolomics (HRM) profiling from 105 pregnant women from the Atlanta African American Maternal-Child cohort (2014-2016). Maternal metabolome perturbations mediating prenatal tobacco smoke exposure and adverse birth outcomes were assessed by an untargeted HRM workflow using generalized linear models, followed by pathway enrichment analysis and chemical annotation, with a meet-in-the-middle approach. The median maternal urinary cotinine concentrations were 5.93 μg/g creatinine and 3.69 μg/g creatinine in early and late pregnancy, respectively. In total, 16,481 and 13,043 metabolic features were identified in serum samples at each visit from positive and negative electrospray ionization modes, respectively. Twelve metabolic pathways were found to be associated with both cotinine concentrations and adverse birth outcomes during early and late pregnancy, including tryptophan, histidine, urea cycle, arginine, and proline metabolism. We confirmed 47 metabolites associated with cotinine levels, preterm birth, and shorter gestational age, including glutamate, serine, choline, and taurine, which are closely involved in endogenous inflammation, vascular reactivity, and lipid peroxidation processes. The metabolic perturbations associated with cotinine levels were related to inflammation, oxidative stress, placental vascularization, and insulin action, which could contribute to shorter gestations. The findings will support the further understanding of potential internal responses in association with tobacco smoke exposures, especially among African American women who are disproportionately exposed to high tobacco smoke and experience higher rates of adverse birth outcomes.

Recurrent preterm birth risk assessment for two delivery subtypes: A multivariable analysis

OBJECTIVE

The study sought to develop and apply a framework that uses a clinical phenotyping tool to assess risk for recurrent preterm birth.

MATERIALS AND METHODS

We extended an existing clinical phenotyping tool and applied a 4-step framework for our retrospective cohort study. The study was based on data collected in the Genomic and Proteomic Network for Preterm Birth Research Longitudinal Cohort Study (GPN-PBR LS). A total of 52 sociodemographic, clinical and obstetric history-related risk factors were selected for the analysis. Spontaneous and indicated delivery subtypes were analyzed both individually and in combination. Chi-square analysis and Kaplan-Meier estimate were used for univariate analysis. A Cox proportional hazards model was used for multivariable analysis.

RESULTS

: A total of 428 women with a history of spontaneous preterm birth qualified for our analysis. The predictors of preterm delivery used in multivariable model were maternal age, maternal race, household income, marital status, previous caesarean section, number of previous deliveries, number of previous abortions, previous birth weight, cervical insufficiency, decidual hemorrhage, and placental dysfunction. The models stratified by delivery subtype performed better than the naïve model (concordance 0.76 for the spontaneous model, 0.87 for the indicated model, and 0.72 for the naïve model).

DISCUSSION

The proposed 4-step framework is effective to analyze risk factors for recurrent preterm birth in a retrospective cohort and possesses practical features for future analyses with other data sources (eg, electronic health record data).

CONCLUSIONS

We developed an analytical framework that utilizes a clinical phenotyping tool and performed a survival analysis to analyze risk for recurrent preterm birth.

Interactions between race/ethnicity, poverty status, and pregnancy cardio-metabolic diseases in prediction of postpartum cardio-metabolic health

Background: Prenatal health disparities exist for African Americans and low socioeconomic status (SES) individuals when compared to non-Hispanic Whites and people of higher SES, particularly in cardio-metabolic diseases. Furthermore, having had a pregnancy-specific cardio-metabolic disease, e.g. preeclampsia, increases risk for future cardio-metabolic disease. Although these factors (race, SES and pregnancy cardio-metabolic disease) are interrelated, studies have rarely considered their combined effect on postpartum cardio-metabolic risk. The purpose of this study was to assess whether SES, race/ethnicity, and prenatal cardio-metabolic disease interact in the prediction of postpartum cardio-metabolic risk. Methods: A sample of 1,753 low-income women of African American, Latina, non-Hispanic White race/ethnicity was recruited after a birth in 5 US sites. Household income was used to categorize poverty status as Poor (< Federal Poverty Level; FPL), near poor (100-200% FPL), or low/middle income (> 200% FPL). Three prenatal cardio-metabolic disease diagnoses (preeclampsia, gestational hypertension, gestational diabetes) were identified from medical records. Four biomarkers (mean arterial pressure, glycosylated haemoglobin, total cholesterol:HDL ratio, and waist-hip ratio) were collected at 6 and 12 months postpartum, and combined into an average postpartum cardio-metabolic risk index. Maternal age, pre-pregnancy body mass index, parity, health behaviors and employment status were covariates. Results: Analyses revealed interactions of race/ethnicity, poverty status, and prenatal cardio-metabolic diseases in the prediction of postpartum cardio-metabolic risk. African American women had higher postpartum cardio-metabolic risk, which was exacerbated following a prenatal cardio-metabolic disease. Low/middle income African American women had higher cardio-metabolic risk compared to poor African American, and all Latina and White women. Conclusions: African American women, and especially those who experienced pregnancy complications, emerged as vulnerable, and greater household income did not appear to confer protection against worse postpartum cardio-metabolic risk for this group. These results highlight the complex interplay between socioeconomic status and race/ethnicity with respect to understanding health disparities.

Does maternal race or ethnicity modify the association between maternal psychiatric disorders and preterm birth?

PURPOSE

Preterm birth risk has been linked to maternal racial and ethnic background, particularly African American heritage; however, the association of maternal race and ethnicity with psychiatric disorders and preterm birth has received relatively limited attention.

METHODS

The Consortium on Safe Labor (2002-2008) is a nationwide U.S. cohort study with 223,394 singleton pregnancies. Clinical data were obtained from electronic medical records, including maternal diagnoses of psychiatric disorders. Relative risk (RR) and 95% confidence intervals (CI) were estimated for the association between maternal psychiatric disorders and preterm birth (<37 completed weeks) using log-binomial regression with generalized estimating equations. The interaction effect of maternal psychiatric disorders with race and ethnicity was also evaluated.

RESULTS

Non-Hispanic White (RR, 1.42; 95% CI, 1.35-1.49), Hispanic (RR, 1.44; 95% CI, 1.29-1.60), and non-Hispanic Black (RR, 1.21, 95% CI, 1.13-1.29) women with any psychiatric disorder were at increased risk for delivering preterm infants, compared with women without any psychiatric disorder. However, non-Hispanic Black women with any psychiatric disorder, depression, bipolar disorder, and schizophrenia had a significantly lower increase in preterm birth risk than non-Hispanic White women.

CONCLUSIONS

Despite the significant association between maternal psychiatric disorders and preterm birth risk, psychiatric disorders did not appear to contribute to racial and ethnic disparities in preterm birth.

Epigenetic age and pregnancy outcomes: GrimAge acceleration is associated with shorter gestational length and lower birthweight

BACKGROUND

Advanced biological aging, as measured by epigenetic aging indices, is associated with early mortality and morbidity. Associations between maternal epigenetic aging indices in pregnancy and pregnancy outcomes, namely gestational length and birthweight, have not been assessed. The purpose of this study was to examine whether epigenetic age during pregnancy was associated with gestational length and birthweight.

RESULTS

The sample consisted of 77 women from the Los Angeles, CA, area enrolled in the Healthy Babies Before Birth study. Whole blood samples for DNA methylation assay were obtained during the second trimester (15.6 ± 2.15 weeks gestation). Epigenetic age indices GrimAge acceleration (GrimAgeAccel), DNAm PAI-1, DNAm ADM, and DNAm cystatin C were calculated. Gestational length and birthweight were obtained from medical chart review. Covariates were maternal sociodemographic variables, gestational age at blood sample collection, and pre-pregnancy body mass index. In separate covariate-adjusted linear regression models, higher early second trimester GrimAgeAccel, b(SE) = - .171 (.056), p = .004; DNAm PAI-1, b(SE) = - 1.95 × 10-4 (8.5 × 10-5), p = .004; DNAm ADM, b(SE) = - .033 (.011), p = .003; and DNAm cystatin C, b(SE) = 2.10 × 10-5 (8.0 × 10-5), p = .012, were each associated with shorter gestational length. Higher GrimAgeAccel, b(SE) = - 75.2 (19.7), p < .001; DNAm PAI-1, b(SE) = - .079(.031), p = .013; DNAm ADM, b(SE) = - 13.8 (3.87), p = .001; and DNAm cystatin C, b(SE) = - .010 (.003), p = .001, were also associated with lower birthweight, independent of gestational length.

DISCUSSION

Higher maternal prenatal GrimAgeAccel, DNAm PAI-1, DNAm ADM, and DNAm cystatin C were associated with shorter gestational length and lower birthweight. These findings suggest that biological age, as measured by these epigenetic indices, could indicate risk for adverse pregnancy outcomes.

Exposures to structural racism and racial discrimination among pregnant and early post-partum Black women living in Oakland, California

Research supports that exposure to stressors (e.g., perceived stress and racism) during pregnancy can negatively impact the immune system, which may lead to infection and ultimately increases the risk for having a preterm or low-birthweight infant. It is well known that Black women report higher levels of stressors at multiple timepoints across pregnancy compared with women of all other racial and ethnic groups. This study addresses gaps in the literature by describing pregnant and early post-partum Black women's exposures to structural racism and self-reported experiences of racial discrimination, and the extent to which these factors are related. We used a cross-sectional study design to collect data related to exposures to racism from pregnant and early post-partum Black women residing in Oakland, California, from January 2016 to December 2017. Comparative analysis revealed that living in highly deprived race + income neighborhoods was associated with experiencing racial discrimination in three or more situational domains (p = .01). Findings show that Black women are exposed to high levels of racism that may have negative impacts on maternal health outcomes.

Defining microbial biomarkers for risk of preterm labor

Preterm birth remains the main contributor to early childhood mortality. The vaginal environment, including microbiota composition, might contribute to the risk of preterm delivery. Alterations in the vaginal microbial community structure might represent a risk factor for preterm birth. Here, we aimed to (a) investigate the association between preterm birth and the vaginal microbial community and (b) identify microbial biomarkers for risk of preterm birth. Microbial DNA was isolated from vaginal swabs in a cohort of 69 women enrolled at hospital admission for their delivery. Microbiota was analyzed by high-throughput 16S rRNA sequencing. While no differences in microbial diversity measures appeared associated with the spontaneous preterm and full-term outcomes, the microbial composition was distinct for these groups. Differential abundance analysis showed Lactobacillus species to be associated with full-term birth whereas an unknown Prevotella species was more abundant in the spontaneous preterm group. Although we studied a very miscegenated population from Brazil, our findings were similar to evidence pointed by other studies in different countries. The role of Lactobacillus species as a protector in the vaginal microbiome is demonstrated to be also a protector of spontaneous preterm outcome whereas the presence of pathogenic species, such as Prevotella spp., is endorsed as a factor of risk for spontaneous preterm delivery.

Neighborhood Gun Violence and Birth Outcomes in Chicago

OBJECTIVES

To examine the association between gun violence and birth outcomes among women in Chicago.

METHODS

Using a 5-year set of birth files (2011-2015) merged with census and police data, birth outcomes including low birth weight (LBW, BW < 2500 g), preterm birth (PTB, < 37 weeks gestation), and small-for-gestational-age (SGA, BW < 10th percentile) were examined among non-Hispanic (NH) white, NH black, and Hispanic women in Chicago. Gun violence rates were categorized into tertiles. Multilevel, multiple logistic regression examined the effects of gun violence and race/ethnicity on birth outcomes.

RESULTS

Of 175,065 births, 10.6% of LBW, 10.6% of PTB, and 9.1% of SGA occurred in high violence tertile. Using white women in low violence tertile as reference, the OR for LBW among black women ranged 1.9-2.1 across all tertiles, and 0.8-1.2 among Hispanic women. OR for PTB for black women were 1.6-1.7 and 1.0-1.2 for Hispanic women, and OR for SGA for black women were 1.6-1.7 and for Hispanic women 0.9-1.0.

CONCLUSIONS FOR PRACTICE

In Chicago, race/ethnicity was associated with birth outcomes, regardless of the level of exposure to gun violence, in 2011-2015. The differences in racial/ethnic composition across the violence exposure levels suggest that, rather than gun violence alone, residential segregation and the geographic inequities likely contribute to disparate birth outcomes.

Socioeconomic Status, Preeclampsia Risk and Gestational Length in Black and White Women

BACKGROUND

Higher socioeconomic status (SES) has less impact on cardio-metabolic disease and preterm birth risk among Black women compared to White women, an effect called "diminishing returns." No studies have tested whether this also occurs for pregnancy cardio-metabolic disease, specifically preeclampsia, or whether preeclampsia risk could account for race-by-SES disparities in birth timing.

METHODS

A sample of 718,604 Black and White women was drawn from a population-based California cohort of singleton births. Education, public health insurance status, gestational length, and preeclampsia diagnosis were extracted from a State-maintained birth cohort database. Age, prenatal care, diabetes diagnosis, smoking during pregnancy, and pre-pregnancy body mass index were covariates.

RESULTS

In logistic regression models predicting preeclampsia risk, the race-by-SES interaction (for both education and insurance status) was significant. White women were at lower risk for preeclampsia, and higher SES further reduced risk. Black women were at higher risk for preeclampsia, and SES did not attenuate risk. In pathway analyses predicting gestational length, an indirect effect of the race-by-SES interaction was observed. Among White women, higher SES predicted lower preeclampsia risk, which in turn predicted longer gestation. The same was not observed for Black women.

CONCLUSIONS

Compared to White women, Black women had increased preeclampsia risk. Higher SES attenuated risk for preeclampsia among White women, but not for Black women. Similarly, higher SES indirectly predicted longer gestational length via reduced preeclampsia risk among White women, but not for Black women. These findings are consistent with diminishing returns of higher SES for Black women with respect to preeclampsia.

Early-life neighborhood context, perceived stress, and preterm birth in African American Women

Stressors from multiple sources, across the life-course, may have independent and joint associations with preterm birth (PTB) risk in African American women. Using data from the Life-course Influences on Fetal Environments Study (LIFE; 2009-2011) of post-partum African American women from Metropolitan Detroit, Michigan (n=1365), we examined the association between perceived stress and PTB, and effect modification by perceptions of early-life neighborhood social control and disorder. We defined PTB as birth before 37 completed weeks of gestation. We used Cohen's Perceived Stress scale, and valid and reliable scales of early-life (age 10) neighborhood social control and social disorder to quantify exposures. We estimated prevalence ratios (PR) and 95% confidence intervals (CI) with log binomial regression models- with separate interaction terms for perceived stress and each early-life neighborhood scale. We considered p < 0.10 significant for interaction terms. PTB occurred in 16.4% (n=224) of the study participants. In the total sample, perceived stress was not associated with PTB rates. However, there was suggestive evidence of a joint association between perceived stress and early-life neighborhood social disorder (p for interaction = 0.06), such that among women who reported high early-life neighborhood social disorder (n=660), perceived stress was positively associated with PTB (adjusted PR: 1.31; 95% CI: 1.05, 1.63). There was no association between perceived stress and PTB for women in the low early-life neighborhood social disorder strata (n=651) (adjusted PR: 0.95, 95% CI: 0.75, 1.21). There was no evidence that early-life neighborhood social control modified the association between perceived stress and PTB. Our results suggest that early-life neighborhood stressors may magnify the association between current perceived stress and PTB rates, in African American women. More research to confirm and explicate the biologic and/or psychosocial mechanisms of the reported association is warranted.

Using Index of Concentration at the Extremes as Indicators of Structural Racism to Evaluate the Association with Preterm Birth and Infant Mortality-California, 2011-2012

Disparities in adverse birth outcomes for Black women continue. Research suggests that societal factors such as structural racism explain more variation in adverse birth outcomes than individual-level factors and societal poverty alone. The Index of Concentration at the Extremes (ICE) measures spatial social polarization by quantifying extremes of deprived and privileged social groups using a single metric and has been shown to partially explain racial disparities in black carbon exposures, mortality, fatal and non-fatal assaults, and adverse birth outcomes such as preterm birth and infant mortality. The objective of this analysis was to assess if local measures of racial and economic segregation as proxies for structural racism are associated and preterm birth and infant mortality experienced by Black women residing in California. California birth cohort files were merged with the American Community Survey by zip code (2011-2012). The ICE was used to quantify privileged and deprived groups (i.e., Black vs. White; high income vs. low income; Black low income vs. White high income) by zip code. ICE scores range from - 1 (deprived) to 1 (privileged). ICE scores were categorized into five quintiles based on sample distributions of these measures: quintile 1 (least privileged)-quintile 5 (most privileged). Generalized linear mixed models were used to test the likelihood that ICE measures were associated with preterm birth or with infant mortality experienced by Black women residing in California. Black women were most likely to reside in zip codes with greater extreme income concentrations, and moderate extreme race and race + income concentrations. Bivariate analysis revealed that greater extreme income, race, and race + income concentrations increased the odds of preterm birth and infant mortality. For example, women residing in least privileged zip codes (quintile 1) were significantly more likely to experience preterm birth (race + income ICE OR = 1.31, 95% CI = 1.72-1.46) and infant mortality (race + income ICE OR = 1.70, 95% CI = 1.17-2.47) compared to women living in the most privileged zip codes (quintile 5). Adjusting for maternal characteristics, income, race, and race + income concentrations remained negatively associated with preterm birth. However, only race and race + income concentrations remained associated with infant mortality. Findings support that ICE is a promising measure of structural racism that can be used to address racial disparities in preterm birth and infant mortality experienced by Black women in California.

Neighborhood deprivation and adverse perinatal outcomes in Sweden: A population-based register study

INTRODUCTION

Neighborhood deprivation has been associated with adverse perinatal outcomes but it is unclear to what extent maternal and social risk factors explain the association and how a stressful environment per se contributes.

MATERIAL AND METHODS

A population-based register study including 218 030 deliveries in Sweden between January 2013 and July 2017 was conducted. Exposure was living in a deprived or severely deprived area defined by the National Operations Department of the Swedish Police Authority. Adverse perinatal outcomes included preterm births, small-for-gestational-age births and stillbirths. A propensity score-based method was used to control for individual baseline characteristics. Associations were investigated with logistic regression analyses and risk estimates are presented as crude (OR) and adjusted odds ratio (aOR) with 95% confidence interval (CI).

RESULTS

Living in a deprived neighborhood in Sweden was associated with extremely preterm births (deprived area OR 1.50, 95% CI 1.07-2.11, severely deprived OR 1.90, 95% CI 1.40-2.58), small-for-gestational-age birth (deprived OR 1.45, 95% CI 1.31-1.60, severely deprived OR 1.85, 95% CI 1.69-2.03) and stillbirth (deprived OR 1.62, 95% CI 1.17-2.26, severely deprived OR 1.56, 95% CI 1.11-2.19). After accounting for individual maternal and social risk factors, the risk of small for gestational age in severely deprived areas remained (aOR 1.45, 95% CI, 1.19-1.75).

CONCLUSIONS

The contextual effect of living in a deprived neighborhood on the risk of extremely preterm births, small-for-gestational-age births and stillbirths was to a high extent explained by individual factors of women residing in exposed areas, yet remained for small-for-gestational-age births in severely deprived areas after adjustment for maternal and social risk factors.

Does smoking during pregnancy mediate educational disparities in preterm delivery? Findings from three large birth cohorts

BACKGROUND

Socio-economic disparities in preterm delivery have often been attributed to socially patterned smoking habits. However, most existing studies have used methods that potentially give biased estimates of the mediating effect of smoking. We used a contemporary mediation approach to study to which extent smoking during pregnancy mediates educational disparities in preterm delivery.

METHODS

We performed a comparative analysis of data from three large birth cohort studies: the Danish National Birth Cohort (DNBC), the Dutch Generation R Study, and the Norwegian Mother and Child Cohort Study (MoBa). Risk of preterm delivery by maternal education is reported as risk differences and decomposed into a part explained by smoking and a part explained by other pathways.

RESULTS

Proportions of preterm singleton deliveries were 4.8%-4.9% in all three cohorts. Total effects of maternal education were 2.0 (95% confidence interval [CI] 1.4, 2.5), 3.2 (95% CI 0.8, 5.2) and 2.0 (95% CI 0.9, 3.0) excess preterm deliveries per 100 singleton deliveries in DNBC, Generation R and MoBa when comparing primary/lower secondary education to an academic degree or equivalent. Smoking mediated, respectively, 22%, 10% and 19% of the excess risk in the DNBC, Generation R and MoBa cohorts. Adjustment for potential misclassification of smoking only increased mediated proportions slightly.

CONCLUSIONS

Smoking during pregnancy explains part of educational disparities in preterm delivery, but the mediated proportion depends on the educational gradient in smoking, emphasising that educational disparities in preterm birth may be mediated by different risk factors in different countries.

Geospatial Analysis of Risk Factors Contributing to Loss to Follow-up in Cleft Lip/Palate Care

Background

Multidisciplinary cleft care depends on follow-up at specified time points to monitor and address functional or aesthetic concerns that may arise during a child's development. However, loss to follow-up (LTFU) is common and can lead to missed opportunities for therapeutic and surgical intervention. This study explores clinical, demographic, and geographic determinants of LTFU in cleft care.

Methods

Medical records were retrospectively evaluated for 558 pediatric patients of a single mid-volume cleft team. The primary outcome was LTFU. Spatial dependency was evaluated using variograms. The probability of LTFU was assessed using a generalized linear geostatistical model within a Bayesian framework. Risk maps were plotted to identify vulnerable communities within our state at higher risk of LTFU.

Results

Younger age at last encounter was a strong predictor of LTFU (P < 0.0001), even when ignoring spatial dependency among observations. When accounting for spatial dependency, lower socioeconomic status [OR = 0.98; 95% CI = (0.97-0.99)] and cleft phenotype [OR = 0.55; 95% CI = (0.36, 0.81)] were significant predictors of LTFU. Distance from the cleft team and rural/urban designation were not statistically significant predictors. Cartographic representation of predicted probability of LTFU revealed vulnerable communities across our state, including in the immediate vicinity of our cleft center.

Conclusions

Geostatistical methods are able to identify risk factors missed by traditional statistical analysis. Knowledge of vulnerable populations allow a cleft team to allocate more resources toward high-risk areas to rectify or prevent deficiencies in care.

Mutations in fetal genes involved in innate immunity and host defense against microbes increase risk of preterm premature rupture of membranes (PPROM)

BACKGROUND

Twin studies have revealed a significant contribution of the fetal genome to risk of preterm birth. Preterm premature rupture of membranes (PPROM) is the leading identifiable cause of preterm delivery. Infection and inflammation of the fetal membranes is commonly found associated with PPROM.

METHODS

We carried out whole exome sequencing (WES) of genomic DNA from neonates born of African-American mothers whose pregnancies were complicated by PPROM (76) or were normal term pregnancies (N = 43) to identify mutations in 35 candidate genes involved in innate immunity and host defenses against microbes. Targeted genotyping of mutations in the candidates discovered by WES was conducted on an additional 188 PPROM cases and 175 controls.

RESULTS

We identified rare heterozygous nonsense and frameshift mutations in several of the candidate genes, including CARD6, CARD8, DEFB1, FUT2, MBL2, NLP10, NLRP12, and NOD2. We discovered that some mutations (CARD6, DEFB1, FUT2, MBL2, NLRP10, NOD2) were present only in PPROM cases.

CONCLUSIONS

We conclude that rare damaging mutations in innate immunity and host defense genes, the majority being heterozygous, are more frequent in neonates born of pregnancies complicated by PPROM. These findings suggest that the risk of preterm birth in African-Americans may be conferred by mutations in multiple genes encoding proteins involved in dampening the innate immune response or protecting the host against microbial infection and microbial products.

Racial disparity in infant mortality

In the United States, African-American infants have significantly higher mortality than white infants. Previous work has identified associations between individual socioeconomic factors and select community-level factors. In this review, the authors look beyond traditional risk factors for infant mortality and examine the social context of race in this country, in an effort to understand African-American women's long-standing birth outcome disadvantage. In the process, recent insights are highlighted concerning neighborhood-level factors such as crime, segregation, built environment, and institutional racism, other likely causes for the poor outcomes of African-American infants in this country compared with infants in most other industrialized nations.

Neighborhood context and birth outcomes: Going beyond neighborhood disadvantage, incorporating affluence

•

Neighborhood affluence protects against the risk of poor birth outcome.

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The protective effect of affluence holds for Whites, Blacks, Hispanics and Asians.

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Mediation of these pathways by prenatal smoking varies by racial group.

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The discourse on neighborhoods and birth outcomes should include affluence.

Transgenerational Transmission of Preterm Birth Risk: The Role of Race and Generational Socio-Economic Neighborhood Context

Objectives We investigated associations of mothers' preterm birth (PTB) status with her infants' PTB risk. We also examined whether this relationship differs by mothers' race and generational socio-economic neighborhood context. Methods Participants were 6592 non-Hispanic (NH) white and NH black mother-infant pairs born in 2009-2011 and 1979-1998, respectively, in Allegheny County, Pennsylvania. Birth records were used to determine gestational age at birth, PTB status (<37 completed weeks of gestation), and PTB subgroups-late and early PTB (34-36 weeks and <34 completed weeks of gestation, respectively). Census data on tract racial composition and household income were used to characterize residential race and economic environment. Logistic regression models were used to calculate Odds Ratios (ORs), Relative Risk Ratios (RRR), and 95% confidence intervals (CIs). Stratified analyses were conducted to assess effect modification. Results Overall, 8.21, 6.63 and 1.58% infants had PTB, LPTB, and EPTB, respectively. Maternal PTB status was associated with a 46% increase in infant PTB (95% CI: 1.08-1.98), EPTB (95% CI: 0.80-2.69), and LPTB (95% CI: 1.04-2.04) risk. Maternal PTB-infant PTB associations, particularly maternal PTB-infant LPTB associations, were stronger among NH blacks, mothers in neighborhoods with a high percentage of NH black residents in both generations, or mothers who moved to neighborhoods with a higher percentage of NH black residents. Conclusions for Practice Race and generational socio-economic neighborhood context modify transgenerational transmission of PTB risk. These findings are important for identification of at-risk populations and to inform future mechanistic studies.

Cumulative effects of prenatal-exposure to exogenous chemicals and psychosocial stress on fetal growth: Systematic-review of the human and animal evidence

BACKGROUND

Adverse effects of prenatal stress or environmental chemical exposures on fetal growth are well described, yet their combined effect remains unclear.

OBJECTIVES

To conduct a systematic review on the combined impact and interaction of prenatal exposure to stress and chemicals on developmental outcomes.

METHODS

We used the first three steps of the Navigation Guide systematic review. We wrote a protocol, performed a robust literature search to identify relevant animal and human studies and extracted data on developmental outcomes. For the most common outcome (fetal growth), we evaluated risk of bias, calculated effect sizes for main effects of individual and combined exposures, and performed a random effects meta-analysis of those studies reporting on odds of low birthweight (LBW) by smoking and socioeconomic status (SES).

RESULTS

We identified 17 human- and 22 animal-studies of combined chemical and stress exposures and fetal growth. Human studies tended to have a lower risk of bias across nine domains. Generally, we found stronger effects for chemicals than stress, and these exposures were associated with reduced fetal growth in the low-stress group and the association was often greater in high stress groups, with limited evidence of effect modification. We found smoking associated with significantly increased odds of LBW, with a greater effect for high stress (low SES; OR 4.75 (2.46-9.16)) compared to low stress (high SES; OR 1.95 (95% CI 1.53-2.48)). Animal studies generally had a high risk of bias with no significant combined effect or effect modification.

CONCLUSIONS

We found that despite concern for the combined effects of environmental chemicals and stress, this is still an under-studied topic, though limited available human studies indicate chemical exposures exert stronger effects than stress, and this effect is generally larger in the presence of stress.

A study on preterm births during 2013-2015, Shiraz, Iran

Preterm birth is the leading cause of neonatal and infant mortality and a substantial portion of neonatal morbidities. The perinatal mortality and morbidity statistics in developing countries are inadequate. In this study, we assessed prevalence and health outcomes of preterm deliveries in tertiary care university hospitals. A retrospective study of hospital records of premature babies born in all the five governmental tertiary care settings during the time interval of 2013-2015 in Shiraz was conducted. Result of this study showed that there was an overall 127.6 premature births per 1000 live births in the study duration. 23.8% of premature newborn had RDS and Incidence of prematurity with RDS was 82.4 per thousand live births. 52.6% of premature newborns were hospitalised in NICU and 8.5% had ROP. Five percent suffered from sepsis and 1% suffered from NEC. Overall mortality was nearly 10% of all the premature newborn. In conclusion, this study showed that premature births and its complications for newborn need to be addressed more in Iran. Impact statement Preterm birth is the leading cause of neonatal mortality and morbidities. Mortality and morbidity statistics related to preterm infants are important healthcare indicators implying the quality of the perinatal health care system and are prerequisite for the identification of problems and implementation of preventive measures. However, the perinatal mortality and morbidity statistics in developing countries are inadequate. The aim of this study was to assess prevalence and health outcome of preterm deliveries in tertiary care university hospitals in Shiraz city, Iran. This study showed that prematurity rate was 12.7%. Among preterm cases, 52.6% were admitted to NICU. RDS occurred among 23.8% of the total premature neonates and 8.2% of the total live births. The incidence of NEC was 1/0% of the total premature neonates and 0.4% of the total live births. The incidence of sepsis was 5% of the premature neonates and 1.9% of the total live births and the incidence of ROP was 8.5% among the premature neonate. The overall mortality of premature neonates was 9.9% of the total premature neonates and 1.2% of the total live births. Rigorous measures for prevention of premature births and its complications for newborns are required in Iran.

Spatial social polarization and birth outcomes: preterm birth and infant mortality - New York City, 2010-14

AIMS

This study assessed the relationship between spatial social polarization measured by the index of the concentration of the extremes (ICE) and preterm birth (PTB) and infant mortality (IM) in New York City. A secondary aim was to examine the ICE measure in comparison to neighborhood poverty.

METHODS

The sample included singleton births to adult women in New York City, 2010-2014 ( n=532,806). Three ICE measures were employed at the census tract level: ICE - Income (persons in households in the bottom vs top 20th percentile of US annual household income), ICE -Race/Ethnicity (black non-Hispanic vs white non-Hispanic populations), and ICE - Income + Race/Ethnicity combined. Preterm birth was defined as birth before 37 weeks' gestation. Infant mortality was defined as a death before one year of age. A two-level generalized linear model with random intercept was utilized adjusting for individual-level covariates.

RESULTS

Preterm birth prevalence was 7.1% and infant mortality rate was 3.4 per 1000 live births. Women who lived in areas with the least privilege were more likely to have a preterm birth or infant mortality as compared to women living in areas with the most privilege. After adjusting for covariates, this association remained for preterm birth (ICE - Income: Adjusted Odds Ratio (AOR) 1.16 (1.10-1.21); ICE - Race/Ethnicity: AOR 1.41 (1.34-1.49); ICE - Income + Race/Ethnicity: AOR 1.36 (1.29-1.43)) and IM (ICE - Race/Ethnicity (AOR 1.80 (1.43-2.28) and ICE - Income + Race/Ethnicity (AOR 1.54 (1.23-1.94)). High neighborhood poverty was associated with PTB only (AOR 1.09 (1.04-1.14).

CONCLUSIONS

These results provide preliminary evidence for the use of the ICE measure in examining structural barriers to healthy birth outcomes.

Prevalence and correlates of alcohol and tobacco use among pregnant women in the United States: Evidence from the NSDUH 2005-2014

Alcohol and tobacco use during pregnancy are among the strongest and most preventable risk factors for adverse neonatal health outcomes, but few developmentally sensitive, population-based studies of this phenomenon have been conducted. To address this gap, the present study examined the prevalence and correlates of alcohol and tobacco use among pregnant adolescents (aged 12-17) and adults (aged 18-44) in the United States. Data were derived from the population-based National Survey of Drug Use and Health (80,498 adolescent and 152,043 adult women) between 2005 and 2014. Findings show disconcerting levels of past-month use among pregnant women with 11.5% of adolescent and 8.7% of adult women using alcohol, and 23.0% of adolescent and 14.9% of adult women using tobacco. Compared to their non-pregnant counterparts, pregnant adolescents were less likely to report past 30-day alcohol use (AOR=0.52, 95% CI=0.36-0.76), but more likely to report past 30-day tobacco use (AOR=2.20, 95% CI=1.53-3.18). Compared to their non-pregnant adult counterparts, pregnant adults were less likely to report using alcohol (AOR=0.06, 95% CI=0.05-0.07) and tobacco (AOR=0.47, 95% CI=0.43-0.52). Compared to pregnant abstainers, pregnant women reporting alcohol/tobacco use were more likely to have had a major depressive episode in the past 12months, report criminal justice system involvement, and endorse comorbid alcohol/tobacco use. Given alcohol and tobacco's deleterious consequences during pregnancy, increased attention to reducing use is critical. Findings suggest that tobacco use is especially problematic for both adolescents and adults and is strongly linked with depression and criminal justice involvement, especially among adults.

Neighborhood Disadvantage and Preterm Delivery in Urban African Americans: The Moderating Role of Religious Coping

Evidence suggests that neighborhood disadvantage predicts preterm delivery (PTD). However, the design of most existing studies precludes within-group analyses, which would allow the identification segments of the population at highest risk, as well as preventive factors. African Americans (AA) are disproportionately affected by PTD, are disproportionately concentrated in disadvantaged neighborhoods, and frequently use religious coping in response to chronic stressors. Our objective was to examine the association between neighborhood disadvantage and PTD, and whether religious coping moderated the associations, among postpartum AA women. Addresses from participants of the Life Influences on Fetal Environments Study (n=1387) were geocoded and linked to data from the American Community Survey. An index of neighborhood disadvantage was derived from a principal components analysis of the following variables: % below poverty, % unemployed, % receiving public assistance income, % college educated, % AA, % female-headed households, % owner occupied homes, median income, and median home value. Three domains of religious coping were assessed: organizational (church attendance), non-organizational (praying for self and asking others for prayer), and personal or subjective (experiences, perceptions, and sentiments about religion), and all were dichotomized as frequent/infrequent or satisfied/not satisfied. Preterm delivery was defined as birth before 37 completed weeks of gestation. Prevalence ratios and 95% confidence intervals were estimated with log binomial regression models. Neighborhood disadvantage did not predict PTD rates in the overall sample. However, there was evidence of moderation by asking others for prayer (P for asking for prayer X disadvantage index interaction term: 0.01). Among women who infrequently asked others for prayer, neighborhood disadvantage was positively associated with PTD rates (adjusted Prevalence ratio: 1.28, 95% Confidence Interval: 1.01, 1.63), and a null association was found for those who frequently asked others for prayer. No evidence of moderation by the other religious coping variables was present. Non-organizational religious coping may buffer against the adverse effects of neighborhood disadvantage on PTD rates, among urban AA women. Future research should examine the mechanisms of the reported relationships.

Acute Impact of Hourly Ambient Air Pollution on Preterm Birth

BACKGROUND

Preterm birth is a major perinatal health problem, but factors leading to it are still not completely understood.

OBJECTIVES

Our goal was to identify the relation between acute increase in ambient air pollution in a few hours before onset of labor and the risk of preterm birth.

METHODS

We collected registered birth outcome data and hourly ambient air pollution measurements during 2009‒2013 in Brisbane, Australia. Using a time-stratified case-crossover design and conditional logistic regression models with natural cubic splines, we assessed the shape of air pollution-preterm birth curve, after controlling for potential confounders. We also examined the effect modification of other factors.

RESULTS

The association between air pollution [nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO)] and preterm birth was nonlinear. Threshold concentrations for the mean of 0‒24 hr NO2, 24‒48 hr SO2, and 24‒48 hr CO before onset of labor were 7.6 parts per billion (ppb), 3.8 ppb, and 162.5 ppb, respectively. Increases in air pollution concentrations above thresholds were associated with increased risks of preterm birth. The odds ratios of preterm birth at the 95th percentile of NO2, SO2, and CO against the thresholds were 1.17 (95% CI: 1.08, 1.27), 1.01 (95% CI: 0.99, 1.04), and 1.18 (95% CI: 1.06, 1.32), respectively. The associations were modified by demographic factors, such as maternal smoking and socioeconomic status.

CONCLUSION

Acute increases in ambient air pollution concentrations above certain levels before onset of labor may stimulate preterm birth.

CITATION

Li S, Guo Y, Williams G. 2016. Acute impact of hourly ambient air pollution on preterm birth. Environ Health Perspect 124:1623-1629; http://dx.doi.org/10.1289/EHP200.

Maternal Race/Ethnicity and Predictors of Pregnancy and Infant Outcomes

Objective. To examine predictors of pregnancy and infant outcomes, including maternal race/ethnicity. Design. Prospective and observational follow-up of high-risk pregnancies and births. Participants. Three hundred fifty-four mothers and their preterm and/or high-risk live-born neonates were closely followed in three tertiary care centers from the prenatal to postnatal periods for potential high-risk and/or preterm births that required neonatal resuscitations. Major Outcome Measures. Pregnancy complications, birth complications, and infant outcomes were examined in conjunction with maternal factors, including preexisting health problems, health behaviors (smoking, alcohol consumption, prenatal visits), and the birth setting (tertiary care centers or community hospitals). Results. About 22% of these infants were transferred into the tertiary care centers from the community hospitals right after birth; the rest were born in the centers. According to regression analyses, predictors of the birth setting were race (White vs. non-White), maternal health behaviors, pregnancy complications, fetal distress, and the presence of congenital defects for infants (p < .001). Predictors for fetal distress included race (Whites) and pregnancy-induced hypertension (p < .003). Predictors for lower birth weight included race (non-Whites), maternal cigarette smoking, pregnancy complications, fetal distress, and congenital defects (p < .001). Infant mortality rate was 3.9% for these high-risk infants, with the highest rate in infants born to Black mothers (8%). Conclusions. There are obvious health disparities among White and non-White women experiencing high-risk pregnancies and births. Future studies are needed to develop interventions targeted to different racial/ethnic groups during pregnancy to reduce preterm and high-risk births.

Differences in Health Behaviors of Hispanic, White, and Black Childbearing Women

Maternal health behaviors such as substance use and sexual promiscuity can put the health of mothers and their offspring at risk. Sociodemographic factors including low socioeconomic status are also found to correlate with health risks for childbearing women. Hispanic women—particularly those less acculturated—often have sociodemographic risk factors present, but have paradoxically positive pregnancy outcomes. This study examines the acculturation and ethnic differences among Hispanic, White, and Black women in health behaviors and attitudes during childbearing, using data from the National Survey of Family Growth Cycle 6 on 1,062 women who were either currently pregnant or had given birth in the past 12 months. Less acculturated Hispanic women had the lowest rates of substance use and reported the least risky sexual behavior compared to Blacks, Whites, and more acculturated Hispanic women, and had the highest levels of agreement with statements valuing traditional maternal roles compared to the other groups.

Association of neighborhood context with offspring risk of preterm birth and low birthweight: A systematic review and meta-analysis of population-based studies

Findings from studies investigating associations of residential environment with poor birth outcomes have been inconsistent. In a systematic review and meta-analysis, we examined associations of neighborhood disadvantage with preterm birth (PTB) and low birthweight (LBW), and explored differences in relationships among racial groups. Two reviewers searched English language articles in electronic databases of published literature. We used random effects logistic regression to calculate odds ratios (and 95% confidence intervals) relating neighborhood disadvantage with PTB and LBW. Neighborhood disadvantage, most disadvantaged versus least disadvantaged neighborhoods, was defined by researchers of included studies, and comprised of poverty, deprivation, racial residential segregation or racial composition, and crime. We identified 1314 citations in the systematic review. The meta-analyses included 7 PTB and 14 LBW cross-sectional studies conducted in the United States (U.S.). Overall, we found 27% [95%CI: 1.16, 1.39] and 11% [95%CI: 1.07, 1.14] higher risk for PTB and LBW among the most disadvantaged compared with least disadvantaged neighborhoods. No statistically significant association was found in meta-analyses of studies that adjusted for race. In race-stratified meta-analyses models, we found 48% [95%CI: 1.25, 1.75] and 61% [95%CI: 1.30, 2.00] higher odds of PTB and LBW among non-Hispanic white mothers living in most disadvantaged neighborhoods compared with those living in least disadvantaged neighborhoods. Similar, but less strong, associations were observed for PTB (15% [95%CI: 1.09, 1.21]) and LBW (17% [95%CI: 1.10, 1.25]) among non-Hispanic black mothers. Neighborhood disadvantage is associated with PTB and LBW, however, associations may differ by race. Future studies evaluating causal mechanisms underlying the associations, and racial/ethnic differences in associations, are warranted.

Adverse childhood experiences are associated with spontaneous preterm birth: a case-control study

BACKGROUND

More than 1 in 10 infants are born prematurely worldwide, making preterm birth the leading cause of neonatal mortality and morbidity. Chronic maternal stress is increasingly recognized as one of the contributing risk factors for preterm birth, yet its specific role remains largely unknown. Examining the exposure to stressors over a mother's life course might provide more perspective on the role of maternal stress in preterm birth. Our aim was therefore to retrospectively explore the associations between chronic, lifelong stressors and protective factors and spontaneous preterm birth.

METHODS

This study was part of a large case-control study based in Edmonton, Canada, examining gene-environment interactions and preterm birth. Cases were mothers with a spontaneous singleton preterm birth (<37 weeks) without preterm premature rupture of membranes. Controls were mothers with an uncomplicated singleton term birth without a history of preterm birth. Sociodemographic and medical data were collected. A postpartum telephone questionnaire was administered to assess stressors across the lifespan. Both individual and contextual variables that could influence stress response systems were examined. Overall, 622 women were included, of which 223 subjects - 75 cases and 148 controls - completed the stress questionnaire. Univariate and multivariate logistic regression analyses were performed.

RESULTS

Multivariate analysis showed that exposure to two or more adverse childhood experiences (ACEs) was associated with a two-fold risk of preterm birth, regardless of maternal age, smoking status, educational status, and history of miscarriage (adjusted OR, 2.09; 95 % CI, 1.10-3.98; P = 0.024). The adjusted odds ratio for the ACE score was 1.18 (95 % CI, 0.99-1.40), suggesting that for every increase in childhood adverse event endorsed, the risk of preterm birth increased by 18 %. Lifetime physical and emotional abuse was also associated with spontaneous preterm birth in our study population (adjusted OR, 1.30; 95 % CI, 1.02-1.65; P = 0.033).

CONCLUSIONS

A strong relationship between ACEs and preterm birth was observed. It has been shown that two or more ACEs have a notable two-fold increase in the risk of spontaneous preterm birth. These data demonstrate that stressors throughout life can have a significant effect on pregnancy outcomes such as preterm birth.

Patterns of social inequalities across pregnancy and birth outcomes: a comparison of individual and neighborhood socioeconomic measures

BACKGROUND

This paper identifies patterns of health inequalities (consistency and magnitude) of socioeconomic disparities for multiple maternal and child health (MCH) outcomes that represent different health care needs of mothers and infants.

METHODS

Using cross-sectional national data (unweighted sample = 6,421, weighted =76,508) from the Canadian Maternity Experiences Survey linked with 2006 Canadian census data, we categorized 25 health indicators of mothers of singletons into five groups of MCH outcomes (A. maternal and infant health status indicators; B. prenatal care; C. maternal experience of labor and delivery; D. neonatal medical care; and E. postpartum infant care and maternal perceptions of health care services). We then examined the association of these health indicators with individual socioeconomic position (SEP) (education and income), neighborhood SEP and combined SEP (a four-level measure of low and high individual and neighborhood SEP), and compared the magnitude (odds ratios and 95% confidence intervals) and direction of the associations within and between MCH outcome groups.

RESULTS

We observed consistent positive gradients of socioeconomic inequalities within most groups and for 23/25 MCH outcomes. However, more significant associations and stronger gradients were observed for the MCH outcomes in the maternal and infant health status group as opposed to other groups. The neonatal medical care outcomes were weakly associated with SEP. The direction of associations was negative between some SEP measures and HIV testing, timing of the first ultrasound, caesarean section, epidural for vaginal births, infant needing non-routine neonatal care after discharge and any breastfeeding at 3 or 6 months. Gradients were steep for individual SEP but moderate for neighborhood SEP. Combined SEP had no consistent gradients but the subcategory of low individual-high neighborhood SEP often showed the poorest health outcomes compared to the categories within this SEP grouping.

CONCLUSION

By examining SEP gradients in multiple MCH outcomes categorized into groups of health care needs, we identified large and consistent inequalities both within and between these groups. Our results suggest differences in pathways and mechanisms contributing to SEP inequalities across groups of MCH outcomes that can be examined in future research and inform prioritization of policies for reducing these inequalities.

Neighborhood socioeconomic disadvantage and gestational weight gain and loss

We explored the relationship between neighborhood socioeconomic disadvantage (NSED) and gestational weight gain and loss and if the association differed by race. A census tract level NSED index (categorized as low, mid-low, mid-high, and high) was generated from 12 measures from the 2000 US Census data. Gestational weight gain and other individual-level characteristics were derived from vital birth records for Allegheny County, PA for 2003-2010 (n = 55,608). Crude and adjusted relative risks were estimated using modified multilevel Poisson regression models to estimate the association between NSED and excessive and inadequate gestational weight gain (GWG) and weight loss (versus adequate GWG). Black women lived in neighborhoods that were more likely to be socioeconomically disadvantaged compared to white women. Almost 55% of women gained an excessive amount of weight during pregnancy, and 2% lost weight during pregnancy. Black women were more likely than white women to have inadequate weight gain or weight loss. Mid-high (aRR = 1.3, 95% CI 1.2, 1.3) and high (aRR = 1.5, 95% CI 1.5, 1.6) NSED compared to low NSED was associated with inadequate weight gain while NSED was not associated with excessive weight gain. Among black women, high versus low NSED was associated with weight loss during pregnancy (RR = 1.6, 95% CI 1.1, 2.5). Among white women, each level of NSED compared to low NSED was associated with weight loss during pregnancy. This study demonstrates how neighborhood socioeconomic characteristics can contribute to our understanding of inadequate weight gain and weight loss during pregnancy, having implications for future research and interventions designed to advance pregnancy outcomes.

A MCP-1 promoter polymorphism at G-2518A is associated with spontaneous preterm birth

Monocyte chemoattractant protein-1 (MCP-1) is an important chemokine involved in the pathogenesis of spontaneous preterm birth (SPTB). We examined whether the MCP-1 G-2518A polymorphism is associated with the risk of SPTB in a Chinese population. The MCP-1 G-2518A polymorphism was genotyped in 569 preterm singleton neonates and in 673 term neonates using polymerase chain reaction-restriction fragment length polymorphism analysis. The distribution of the MCP-1 G-2518A genotype and the allele frequencies between the SPTB patients and the controls were not significantly different in the overall sample. However, we found that the AA genotype was associated with significantly increased susceptibility to very SPTB (<32 weeks) [odds ratio (OR) 2.07; 95 % confidence interval (CI), 1.27-3.36; P = 0.005) and extremely SPTB (<28 weeks) (OR 2.74; 95 % CI, 1.10-6.72; P = 0.014) compared with -2518G-positive genotypes (GG + GA genotypes). When extremely preterm neonates and very preterm neonates were combined, the AA genotype was also significantly associated with increased susceptibility to SPTB (OR 2.23; 95 % CI, 1.40-3.54; P < 0.001). The MCP-1 G-2518A polymorphism was not associated with increased susceptibility to SPTB in patients with premature rupture of the membranes (PROM) or in those without PROM. Our findings suggest that the MCP-1 G-2518A polymorphism may plays a role in mediating the susceptibility to SPTB in the Chinese population. Knowledge of genetic factors contributing to the pathogenesis of SPTB may have implications for screening and treatment of this disorder.

Neighbourhood socio-economic status and spontaneous premature birth in Alberta

OBJECTIVE

To evaluate a possible association between neighbourhood socio-economic status and spontaneous premature birth in Alberta births.

METHODS

The study design was a retrospective cohort of all births in Alberta for the years 2001 and 2006. The primary outcome was spontaneous preterm birth at &lt;37 weeks gestation. Neighbourhood socio-economic status was measured by the Pampalon Material Deprivation Index for each Statistics Canada census dissemination area. Births were linked to dissemination area using maternal postal codes.

RESULTS

The analysis comprised 73,585 births, in which the rate of spontaneous preterm delivery at &lt;37 weeks was 5.3%. The rates of spontaneous preterm delivery for each neighbourhood socio-economic category ranged from 4.9% (95% CI 4.5%-5.2%) in the highest category to 6.3% (95% CI 6.0%-6.7%) in the lowest (p&lt;0.001). After controlling for smoking, parity, maternal age and year, we found that women living in the highest socio-economic status neighbourhoods had an adjusted spontaneous preterm birth rate of 5.1% (95% CI 4.7%-5.5%) compared to 6.0% (95% CI 5.6%-6.4%) for women living in the lowest (p=0.003).

CONCLUSION

This study documented a modest increase in the risk of spontaneous preterm birth with low socio-economic status. The possibility of confounding bias cannot be ruled out.

Neighborhood socioeconomic disadvantage and gestational weight gain and loss

We explored the relationship between neighborhood socioeconomic disadvantage (NSED) and gestational weight gain and loss and if the association differed by race. A census tract level NSED index (categorized as low, mid-low, mid-high, and high) was generated from 12 measures from the 2000 US Census data. Gestational weight gain and other individual-level characteristics were derived from vital birth records for Allegheny County, PA for 2003-2010 (n = 55,608). Crude and adjusted relative risks were estimated using modified multilevel Poisson regression models to estimate the association between NSED and excessive and inadequate gestational weight gain (GWG) and weight loss (versus adequate GWG). Black women lived in neighborhoods that were more likely to be socioeconomically disadvantaged compared to white women. Almost 55% of women gained an excessive amount of weight during pregnancy, and 2% lost weight during pregnancy. Black women were more likely than white women to have inadequate weight gain or weight loss. Mid-high (aRR = 1.3, 95% CI 1.2, 1.3) and high (aRR = 1.5, 95% CI 1.5, 1.6) NSED compared to low NSED was associated with inadequate weight gain while NSED was not associated with excessive weight gain. Among black women, high versus low NSED was associated with weight loss during pregnancy (RR = 1.6, 95% CI 1.1, 2.5). Among white women, each level of NSED compared to low NSED was associated with weight loss during pregnancy. This study demonstrates how neighborhood socioeconomic characteristics can contribute to our understanding of inadequate weight gain and weight loss during pregnancy, having implications for future research and interventions designed to advance pregnancy outcomes.

Contextualizing racial disparities in preterm delivery: a rhetorical analysis of U.S. epidemiological research at the turn of the 21st century

Preterm delivery (PTD), defined as delivery prior to 37 weeks gestation, is a key contributor to persistent racial disparities in infant mortality in the United States. Five major funding initiatives were devoted to advancing PTD epidemiology during the 1990s and 2000s. By examining content and rhetorical features of 94 studies conducted under these initiatives, and published between 1993 and 2011, this paper considers how calls for more "contextual" approaches (focusing on social and environmental contexts) interacted with more "conventional" approaches (focusing on individual-level risk factors) to PTD epidemiology during this period. Contextual advocates initially emphasized complex biosocial reasoning to better connect social adversity with embodied outcomes. Yet responses by researchers invested in conventional approaches, as well as in studies published under new initiatives that explicitly claimed to incorporate contextual insights, often reframed this complex reasoning in biologically reductionist terms. Subsequent contextual advocates then focused on developing statistical methods to support research about social and environmental causes of PTD, and this strategy appears to have gained some traction with conventional researchers. These findings call for closer attention to language and power in both social scientific studies of epidemiological knowledge production, as well as among epidemiologists themselves.

Neighborhood Disadvantage, Preconception Health Behaviors and Infant Birthweight: A Preliminary Study

Prior studies have shown that neighborhood disadvantage and disorder are associated with birth outcomes. This study examined preconception diet and physical activity level, as well as body mass index, as mediators of the association between neighborhood conditions and birthweight. Secondary data analyses were conducted using data from the National Longitudinal Study of Adolescent Health (Add Health). The final analytic sample consisted of 523 adolescent and young adult mothers giving singleton live births between 1997 and 1998. In contrast to previous research, we found that neighborhood characteristics were unrelated to birthweight. Consistent with prior studies, compared to those who were White, on average, Blacks had birthweights that were 163.25 grams lighter. In addition, compared to mothers who were married or living with a partner, mothers who did not have a partner at the time of birth, on average, had offspring that were 127.20 grams lighter. No evidence was found for the mediation hypotheses as there were no associations between neighborhood characteristics and preconception diet or physical activity or between these behavioral variables and birthweight. To the authors' knowledge, this is the first study examining diet and physical activity as possible behavioral pathways between the neighborhood context and birthweight.

A spatially filtered multilevel model to account for spatial dependency: application to self-rated health status in South Korea

Background

This study aims to suggest an approach that integrates multilevel models and eigenvector spatial filtering methods and apply it to a case study of self-rated health status in South Korea. In many previous health-related studies, multilevel models and single-level spatial regression are used separately. However, the two methods should be used in conjunction because the objectives of both approaches are important in health-related analyses. The multilevel model enables the simultaneous analysis of both individual and neighborhood factors influencing health outcomes. However, the results of conventional multilevel models are potentially misleading when spatial dependency across neighborhoods exists. Spatial dependency in health-related data indicates that health outcomes in nearby neighborhoods are more similar to each other than those in distant neighborhoods. Spatial regression models can address this problem by modeling spatial dependency. This study explores the possibility of integrating a multilevel model and eigenvector spatial filtering, an advanced spatial regression for addressing spatial dependency in datasets.

Methods

In this spatially filtered multilevel model, eigenvectors function as additional explanatory variables accounting for unexplained spatial dependency within the neighborhood-level error. The specification addresses the inability of conventional multilevel models to account for spatial dependency, and thereby, generates more robust outputs.

Results

The findings show that sex, employment status, monthly household income, and perceived levels of stress are significantly associated with self-rated health status. Residents living in neighborhoods with low deprivation and a high doctor-to-resident ratio tend to report higher health status. The spatially filtered multilevel model provides unbiased estimations and improves the explanatory power of the model compared to conventional multilevel models although there are no changes in the signs of parameters and the significance levels between the two models in this case study.

Conclusions

The integrated approach proposed in this paper is a useful tool for understanding the geographical distribution of self-rated health status within a multilevel framework. In future research, it would be useful to apply the spatially filtered multilevel model to other datasets in order to clarify the differences between the two models. It is anticipated that this integrated method will also out-perform conventional models when it is used in other contexts.

The social determinants of infant mortality and birth outcomes in Western developed nations: a cross-country systematic review

Infant mortality (IM) and birth outcomes, key population health indicators, have lifelong implications for individuals, and are unequally distributed globally. Even among western industrialized nations, striking cross-country and within-country patterns are evident. We sought to better understand these variations across and within the United States of America (USA) and Western Europe (WE), by conceptualizing a social determinants of IM/birth outcomes framework, and systematically reviewing the empirical literature on hypothesized social determinants (e.g., social policies, neighbourhood deprivation, individual socioeconomic status (SES)) and intermediary determinants (e.g., health behaviours). To date, the evidence suggests that income inequality and social policies (e.g., maternal leave policies) may help to explain cross-country variations in IM/birth outcomes. Within countries, the evidence also supports neighbourhood SES (USA, WE) and income inequality (USA) as social determinants. By contrast, within-country social cohesion/social capital has been underexplored. At the individual level, mixed associations have been found between individual SES, race/ethnicity, and selected intermediary factors (e.g., psychosocial factors) with IM/birth outcomes. Meanwhile, this review identifies several methodological gaps, including the underuse of prospective designs and the presence of residual confounding in a number of studies. Ultimately, addressing such gaps including through novel approaches to strengthen causal inference and implementing both health and non-health policies may reduce inequities in IM/birth outcomes across the western developed world.

Risk of miscarriage among black women and white women in a U.S. Prospective Cohort Study

Many adverse pregnancy outcomes differ by race. We examined the association between self-reported race and miscarriage (pregnancy loss at <20 weeks) in a community-based pregnancy cohort. Women from the southeastern United States (North Carolina, Texas, and Tennessee) were enrolled in "Right from the Start" from 2000 to 2009. They were recruited while trying to conceive or during early pregnancy. Participants completed study ultrasound examinations, interviews, and consent forms for review of medical records. We used proportional hazard models to examine miscarriage risk among black women compared with white women, adjusted for confounders. There were 537 observed miscarriages among 4,070 women, 23% of whom self-identified as black (n = 932). The life table-adjusted cumulative risk of loss after gestational week 5 was 21.3%. With adjustment for age and alcohol use, blacks had increased risk of miscarriage compared with whites (adjusted hazard ratio = 1.57, 95% confidence interval: 1.27, 1.93). When risk of loss before gestational week 10 was dichotomized at the median gestational age, there was little difference, but black women had a greater risk thereafter compared with white women (adjusted hazard ratio = 1.93, 95% confidence interval: 1.48, 2.51). Early pregnancy ultrasound examinations did not differ by race. In summary, self-reported race is independently associated with risk of miscarriage, and the higher risk for black women is concentrated in gestational weeks 10-20.

Neighborhood socioeconomic status in relation to preterm birth in a U.S. cohort of black women

This study examines the association between neighborhood socioeconomic status (SES) and preterm birth among U.S. black women. A composite variable for neighborhood SES, derived from 7 U.S. Census Bureau indicators, was assessed in relation to self-reported preterm birth (505 spontaneous and 452 medically indicated) among 6,390 women in the Black Women's Health Study who delivered singleton births during 1995-2003. The odds ratio (OR) for preterm birth, comparing the lowest (most deprived) to the highest (least deprived) quartiles of neighborhood SES, was 0.98 (95% CI, 0.80, 1.20) after adjustment for individual-level characteristics. Low neighborhood SES was not associated with spontaneous or medically indicated preterm birth overall or within strata of maternal age, education, or geographic region. The only significant finding was higher odds of medically indicated preterm birth associated with low neighborhood SES among unmarried women. Low neighborhood SES was not materially associated with preterm birth in this study of U.S. Black women.