The Association Between Adverse Childhood Experiences and Preterm Delivery: A Latent Class Approach.

Background: Racial and socioeconomic status (SES) disparities in preterm delivery (PTD) have existed in the United States for decades. Disproportionate maternal exposures to adverse childhood experiences (ACEs) may increase the risk for adverse birth outcomes. Moreover, racial and SES disparities exist in the prevalence of ACEs, underscoring the need for research that examines whether ACEs contribute to racial and SES disparities in PTD. Methods: We examined the relationship between ACEs and PTD in a longitudinal sample of N = 3,884 women from the National Longitudinal Study of Adolescent to Adult Health (1994-2018). We applied latent class analysis to (1) identify subgroups of women characterized by patterns of ACE occurrence; (2) estimate the association between latent class membership (LCM) and PTD, and (3) examine whether race and SES influence LCM or the association between LCM and PTD. Results: Two latent classes were identified, with women in the high ACEs class characterized by a higher probability of emotional abuse, physical abuse, sexual abuse, and foster care placement compared with the low ACEs class, but neither class was associated with PTD. Race and SES did not predict LCM. Conclusions: Our findings suggest that ACEs may not impact PTD risk in previously hypothesized ways. Future research should assess the impact of ACEs on the probability of having live birth pregnancies as well as the role of potential protective factors in mitigating the impact of ACEs on PTD.

Structural gendered racism and preterm birth inequities in the United States.

Structural gendered racism - the "totality of interconnectedness between structural racism and sexism" - is conceptualized as a fundamental cause of the persistent preterm birth inequities experienced by Black and Indigenous people in the United States. Our objective was to develop a state-level latent class measure of structural gendered racism and examine its association with preterm birth among all singleton live births in the US in 2019. Using previously-validated inequity indicators between White men and Black women across 9 domains (education, employment, poverty, homeownership, health insurance, segregation, voting, political representation, incarceration), we conducted a latent profile analysis to identify a latent categorical variable with k number of classes that have similar values on the observed continuous input variables. Racialized group-stratified multilevel modified Poisson regression models with robust variance and random effects for state assessed the association between state-level classes and preterm birth. We found four distinct latent classes that were all characterized by higher levels of disadvantage for Black women and advantages for White men, but the magnitude of that difference varied by latent class. We found preterm birth risk among Black birthing people was higher across all state-level latent classes compared to White birthing people, and there was some variation of preterm birth risk across classes among Black but not White birthing people. These findings further emphasize the importance of understanding and interrogating the whole system and the need for multifaceted policy solutions.

Lifetime Upward Economic Mobility and US-Born Latina Women's Preterm Birth Rates.

OBJECTIVES: To determine whether Latina women's upward economic mobility from early-life residence in impoverished urban neighborhoods is associated with preterm birth (< 37 weeks, PTB) . METHODS: Multivariate logistic regression analyses were performed on the Illinois transgenerational birth-file with appended US census income information for Hispanic infants (born 1989-1991) and their mothers (born 1956-1976). RESULTS: In Chicago, modestly impoverished-born Latina women (n = 1,674) who experienced upward economic mobility had a PTB rate of 8.5% versus 13.1% for those (n = 3,760) with a lifelong residence in modestly impoverished neighborhoods; the unadjusted and adjusted (controlling for age, marital status, adequacy of prenatal care, and cigarette smoking) RR equaled 0.65 (0.47, 0.90) and 0.66 (0.47, 0.93), respectively. Extremely impoverished-born Latina women (n = 2,507) who experienced upward economic mobility across their life-course had a PTB rate of 12.7% versus 15.9% for those (n = 3,849) who had a lifelong residence in extremely impoverished neighborhoods, the unadjusted and adjusted RR equaled 0.8 (0.63. 1.01) and 0.95 (0.75, 1.22), respectively. CONCLUSIONS FOR PRACTICE: Latina women's upward economic mobility from early-life residence in modestly impoverished urban neighborhoods is associated with a decreased risk of PTB. A similar trend is absent among their peers with an early-life residence in extremely impoverished areas.

Addressing anti-black racism in an academic preterm birth initiative: perspectives from a mixed methods case study.

BACKGROUND: Growing recognition of racism perpetuated within academic institutions has given rise to anti-racism efforts in these settings. In June 2020, the university-based California Preterm Birth Initiative (PTBi) committed to an Anti-Racism Action Plan outlining an approach to address anti-Blackness. This case study assessed perspectives on PTBi's anti-racism efforts to support continued growth toward racial equity within the initiative. METHODS: This mixed methods case study included an online survey with multiple choice and open-ended survey items (n = 27) and key informant interviews (n = 8) of leadership, faculty, staff, and trainees working within the initiative. Survey and interview questions focused on perspectives about individual and organizational anti-racism competencies, perceived areas of initiative success, and opportunities for improvement. Qualitative interview and survey data were coded and organized into common themes within assessment domains. RESULTS: Most survey respondents reported they felt competent in all the assessed anti-racism skills, including foundational knowledge and responding to workplace racism. They also felt confident in PTBi's commitment to address anti-Blackness. Fewer respondents were clear on strategic plans, resources allocated, and how the anti-racism agenda was being implemented. Suggestions from both data sources included further operationalizing and communicating commitments, integrating an anti-racism lens across all activities, ensuring accountability including staffing and funding consistent with anti-racist approaches, persistence in hiring Black faculty, providing professional development and support for Black staff, and addressing unintentional interpersonal harms to Black individuals. CONCLUSIONS: This case study contributes key lessons which move beyond individual-level and theoretical approaches towards transparency and accountability in academic institutions aiming to address anti-Black racism. Even with PTBi's strong commitment and efforts towards racial equity, these case study findings illustrate that actions must have sustained support by the broader institution and include leadership commitment, capacity-building via ongoing coaching and training, broad incorporation of anti-racism practices and procedures, continuous learning, and ongoing accountability for both short- and longer-term sustainable impact.

The Black-White Disparity in Preterm Birth: Race or Racism?

Policy Points Racism is an upstream determinant of health that influences health through many midstream and downstream factors. This Perspective traces multiple plausible causal pathways from racism to preterm birth. Although the article focuses on the Black-White disparity in preterm birth, a key population health indicator, it has implications for many other health outcomes. It is erroneous to assume by default that underlying biological differences explain racial disparities in health. Appropriate science-based policies are needed to address racial disparities in health; this will require addressing racism.

Risk of Adverse Pregnancy Outcomes Among Pregnant Individuals With Gestational Diabetes by Race and Ethnicity in the United States, 2014-2020.

Importance: Gestational diabetes, which increases the risk of adverse pregnancy outcomes, has been increasing in frequency across all racial and ethnic subgroups in the US. Objective: To assess whether the frequency of adverse pregnancy outcomes among those in the US with gestational diabetes changed over time and whether the risk of these outcomes differed by maternal race and ethnicity. Design, Setting, and Participants: Exploratory serial, cross-sectional, descriptive study using US National Center for Health Statistics natality data for 1 560 822 individuals with gestational diabetes aged 15 to 44 years with singleton nonanomalous live births from 2014 to 2020 in the US. Exposures: Year of delivery and race and ethnicity, as reported on the birth certificate, stratified as non-Hispanic American Indian, non-Hispanic Asian/Pacific Islander, non-Hispanic Black, Hispanic/Latina, and non-Hispanic White (reference group). Main Outcomes and Measures: Maternal outcomes of interest included cesarean delivery, primary cesarean delivery, preeclampsia or gestational hypertension, intensive care unit (ICU) admission, and transfusion; neonatal outcomes included large for gestational age (LGA), macrosomia (>4000 g at birth), small for gestational age (SGA), preterm birth, and neonatal ICU (NICU) admission, as measured by the frequency (per 1000 live births) with estimation of mean annual percentage change (APC), disparity ratios, and adjusted risk ratios. Results: Of 1 560 822 included pregnant individuals with gestational diabetes (mean [SD] age, 31 [5.5] years), 1% were American Indian, 13% were Asian/Pacific Islander, 12% were Black, 27% were Hispanic/Latina, and 48% were White. From 2014 to 2020, there was a statistically significant increase in the overall frequency (mean APC per year) of preeclampsia or gestational hypertension (4.2% [95% CI, 3.3% to 5.2%]), transfusion (8.0% [95% CI, 3.8% to 12.4%]), preterm birth at less than 37 weeks (0.9% [95% CI, 0.3% to 1.5%]), and NICU admission (1.0% [95% CI, 0.3% to 1.7%]). There was a significant decrease in cesarean delivery (-1.4% [95% CI, -1.7% to -1.1%]), primary cesarean delivery (-1.2% [95% CI, -1.5% to -0.9%]), LGA (-2.3% [95% CI, -2.8% to -1.8%]), and macrosomia (-4.7% [95% CI, -5.3% to -4.0%]). There was no significant change in maternal ICU admission and SGA. In comparison with White individuals, Black individuals were at significantly increased risk of all assessed outcomes, except LGA and macrosomia; American Indian individuals were at significantly increased risk of all assessed outcomes except cesarean delivery and SGA; and Hispanic/Latina and Asian/Pacific Islander individuals were at significantly increased risk of maternal ICU admission, preterm birth, NICU admission, and SGA. Differences in adverse outcomes by race and ethnicity persisted through these years. Conclusions and Relevance: From 2014 through 2020, the frequency of multiple adverse pregnancy outcomes in the US increased among pregnant individuals with gestational diabetes. Differences in adverse outcomes by race and ethnicity persisted.

Integrative Review of Racial Disparities in Perinatal Outcomes Among Beneficiaries of the Military Health System.

OBJECTIVE: To examine the extent to which racial disparities exist in the perinatal outcomes of beneficiaries of the Military Health System (MHS). DATA SOURCES: We searched the PubMed, CINAHL, and Embase databases. STUDY SELECTION: We selected articles published in English in peer-reviewed journals in which the authors examined race in relation to perinatal outcomes among beneficiaries of the MHS. Date of publication was unrestricted through March 2021. DATA EXTRACTION: Twenty-six articles met the inclusion criteria. We extracted data about study design, purpose, sample, setting, and results. We also assigned quality appraisal ratings to each article. DATA SYNTHESIS: In most of the included articles, researchers observed differences in perinatal outcomes between Black and White women. Compared to White women, Black women had greater rates of cesarean birth, preterm birth, low birth weight, and small for gestational age neonates. White women had greater rates of postpartum depression than Black women. CONCLUSION: Racial disparities in very low birth weight newborns and preterm birth may be smaller in the MHS than in the general population of the United States. The overall rates of preterm birth, cesarean birth, and neonatal mortality were lower for beneficiaries of the MHS than in the general population of the United States.

Association of Residence in High-Police Contact Neighborhoods With Preterm Birth Among Black and White Individuals in Minneapolis.

Importance: Police contact may have negative psychological effects on pregnant people, and psychological stress has been linked to preterm birth (ie, birth at <37 weeks' gestation). Existing knowledge of racial disparities in policing patterns and their associations with health suggest redesigning public safety policies could contribute to racial health equity. Objective: To examine the association between community-level police contact and the risk of preterm birth among White pregnant people, US-born Black pregnant people, and Black pregnant people who were born outside the US. Design, Setting, and Participants: This cross-sectional study used medical record data of 745 White individuals, 121 US-born Black individuals, and 193 Black individuals born outside the US who were Minneapolis residents and gave birth to a live singleton at a large health system between January 1 and December 31, 2016. Data were analyzed from March 2019 to October 2020. Exposures: Police contact was measured at the level of the census tract where the pregnant people lived. Police incidents per capita (ie, the number of police incidents divided by the census tract population estimate) were dichotomized into high if the value was in the fourth quartile and low for the remaining three quartiles. Main Outcomes and Measures: Preterm birth status was based on the International Statistical Classification of Diseases and Related Health Problems, 10th revision, Clinical Modification (ICD-10-CM) code. Preterm infants were those with ICD-10-CM codes P07.2 and P07.3 documented in their charts. Results: Of 1059 pregnant people (745 [70.3%] White, 121 [11.4%] US-born Black, 193 [18.2%] Black born outside the US) in the sample, 336 White individuals (45.1%) and 62 Black individuals who were born outside the US (32.1%) gave birth between the ages of 30 and 34 years, while US-born Black individuals gave birth at younger ages, with 49 (40.5%) aged 25 years or younger. The incidence of preterm birth was 6.7% for White individuals (50 pregnant people), 14.0% for US-born Black individuals (17 pregnant people), and 5.7% for Black individuals born outside the US (11 pregnant people). In areas with high police contact vs low police contact, the odds of preterm birth were 90% higher for White individuals (odds ratio [OR], 1.9; 95% CI, 1.9-2.0), 100% higher for US-born Black individuals (OR, 2.0; 95% CI, 1.8-2.2), and 10% higher for Black individuals born outside the US (OR, 1.1; 95% CI, 1.0-1.2). Secondary geospatial analysis further revealed that the proportion of Black residents in Minneapolis census tracts was correlated with the number of police incidents reported between 2012 and 2016 (P = .001). Conclusions and Relevance: In this study, police contact was associated with preterm birth for both Black and White pregnant people. Predominantly Black neighborhoods had greater police contact than predominantly White neighborhoods, indicating that Black pregnant people were more likely to be exposed to police than White pregnant people. These findings suggest that racialized police patterns borne from a history of racism in the United States may contribute to racial disparity in preterm birth.

Maternal biological age assessed in early pregnancy is associated with gestational age at birth.

Maternal age is an established predictor of preterm birth independent of other recognized risk factors. The use of chronological age makes the assumption that individuals age at a similar rate. Therefore, it does not capture interindividual differences that may exist due to genetic background and environmental exposures. As a result, there is a need to identify biomarkers that more closely index the rate of cellular aging. One potential candidate is biological age (BA) estimated by the DNA methylome. This study investigated whether maternal BA, estimated in either early and/or late pregnancy, predicts gestational age at birth. BA was estimated from a genome-wide DNA methylation platform using the Horvath algorithm. Linear regression methods assessed the relationship between BA and pregnancy outcomes, including gestational age at birth and prenatal perceived stress, in a primary and replication cohort. Prenatal BA estimates from early pregnancy explained variance in gestational age at birth above and beyond the influence of other recognized preterm birth risk factors. Sensitivity analyses indicated that this signal was driven primarily by self-identified African American participants. This predictive relationship was sensitive to small variations in the BA estimation algorithm. Benefits and limitations of using BA in translational research and clinical applications for preterm birth are considered.

Endocrine disrupting chemical-associated hair product use during pregnancy and gestational age at delivery: a pilot study.

BACKGROUND: Prenatal endocrine disrupting chemical (EDC) exposure has been associated with increased risk of preterm birth. Non-Hispanic Black women have higher incidence of preterm birth compared to other racial/ethnic groups and may be disproportionately exposed to EDCs through EDC-containing hair products. However, research on the use of EDC-associated hair products during pregnancy and risk of preterm birth is lacking. Therefore, the objective of this pilot study was to estimate associations of prenatal hair product use with gestational age at delivery in a Boston, Massachusetts area pregnancy cohort. METHODS: The study population consisted of a subset of participants enrolled in the Environmental Reproductive and Glucose Outcomes (ERGO) Study between 2018 and 2020. We collected self-reported data on demographics and hair product use using a previously validated questionnaire at four prenatal visits (median: 12, 19, 26, 36 weeks' gestation) and abstracted gestational age at delivery from medical records. We compared gestational age and hair product use by race/ethnicity and used linear regression to estimate covariate-adjusted associations of product use and frequency of use at each study visit with gestational age at delivery. Primary models were adjusted for maternal age at enrollment and delivery method. RESULTS: Of the 154 study participants, 7% delivered preterm. Non-Hispanic Black participants had lower mean gestational age at delivery compared to non-Hispanic White participants (38.2 vs. 39.2 weeks) and were more likely to report ever and more frequent use of hair products. In regression models, participants reporting daily use of hair oils at visit 4 had lower mean gestational age at delivery compared to non-users (ß: -8.3 days; 95% confidence interval: -14.9, -1.6). We did not find evidence of associations at earlier visits or with other products. CONCLUSIONS: Frequent use of hair oils during late pregnancy may be associated with shorter gestational duration. As hair oils are more commonly used by non-Hispanic Black women and represent potentially modifiable EDC exposure sources, this may have important implications for the known racial disparity in preterm birth.

Reproductive and obstetric outcomes in women of racial minorities aged 40 years and older undergoing IVF.

RESEARCH QUESTION: Do women of racial minorities aged 40 years or older have similar reproductive and obstetric outcomes as white women undergoing IVF? DESIGN: A retrospective cohort study conducted at a single academic university-affiliated centre. The study population included women aged 40 years or older undergoing their first IVF cycle with fresh cleavage-stage embryo transfer stratified by racial minority status: minority (black or Asian) versus white. Clinical intrauterine pregnancy and live birth rate were the primary outcomes. Preterm delivery (<37 weeks) and small for gestational age were the secondary outcomes. Odds ratios with 95% confidence intervals were estimated. P < 0.05 was considered to be statistically significant. RESULTS: A total of 2050 cycles in women over the age of 40 years were analysed, 561 (27.4%) of which were undertaken by minority women and 1489 (72.6%) by white women. Minority women were 30% less likely to achieve a pregnancy compared with their white (non-Hispanic) counterparts (adjusted OR 0.68, CI 0.54 to 0.87). Once pregnant, however, the odds of live birth were similar (adjusted OR 1.23, CI 0.91 to 1.67). Minority women were significantly more likely to have lower gestational ages at time of delivery (38.5 versus 39.2 weeks, P = 0.009) and were more likely to have extreme preterm birth delivery 24-28 weeks (5.5 versus 1.0%, P = 0.021). CONCLUSION: Minority women of advanced reproductive age are less likely to achieve a pregnancy compared with white (non-Hispanic) women. Once pregnancy is achieved, however, live birth rates are similar albeit with minority women experiencing higher rates of preterm delivery.

Analysis of State-Level Immigrant Policies and Preterm Births by Race/Ethnicity Among Women Born in the US and Women Born Outside the US.

Importance: Criminalizing immigrant policies, a form of structural racism, are associated with preterm birth; however, to date, few population studies have examined this association by race and nativity status or examined the association of inclusive immigrant policies with preterm birth. Objective: To assess the extent to which variation in preterm birth by race/ethnicity and nativity status is associated with state-level criminalizing vs inclusive immigrant policies. Design, Setting, and Participants: This retrospective, cross-sectional study analyzed birth record data from all 50 states and the District of Columbia in 2018, as well as state-level indicators of inclusive and criminalizing immigrant policies. White, Black, Asian, and Latina women who had singleton births were included in the study. Statistical analysis was performed from June 1, 2020, to February 5, 2021. Two continuous variables were created to capture the number of criminalizing vs inclusive immigrant policies in effect as of 2017 in each state. Main Outcomes and Measures: The main outcome measure was preterm birth (<37 weeks' gestation). Results: Among the 3 455 514 live births that occurred in 2018, 10.0% were preterm, and 23.2% were to mothers born outside the US. Overall, for women born outside the US, each additional state-level inclusive policy was associated with a 2% decrease in preterm birth (adjusted odds ratio [aOR], 0.98 [95% CI, 0.96-1.00]); there were no significant associations between inclusive policies and preterm birth among women born in the US. In models examining the combined associations of criminalizing and inclusive immigrant policies with preterm birth, each additional criminalizing policy was associated with a 5% increase in preterm birth among Black women born outside the US (aOR, 1.05 [95% CI, 1.00-1.10]). Each additional inclusive immigrant policy was associated with a lower likelihood of preterm birth for Asian women born in the US (aOR, 0.95 [95% CI, 0.93-0.98]) and White women born outside the US (aOR, 0.97 [95% CI, 0.95-0.99]). No significant associations were found among other groups. Conclusions and Relevance: This study suggests that criminalizing immigrant policies are associated with an increase in preterm birth specifically for Black women born outside the US. Inclusive immigrant policies are associated with a decrease in preterm birth for immigrants overall, Asian women born in the US, and White women born outside the US. No associations were found between criminalizing or inclusive immigrant policies and preterm birth among Latina women.

Racial/Ethnic Disparities in Very Preterm Birth and Preterm Birth Before and During the COVID-19 Pandemic.

Importance: The coronavirus disease 2019 (COVID-19) pandemic may exacerbate existing racial/ethnic inequities in preterm birth. Objective: To assess whether racial/ethnic disparities in very preterm birth (VPTB) and preterm birth (PTB) increased during the first wave of the COVID-19 pandemic in New York City. Design, Setting, and Participants: This cross-sectional study included 8026 Black, Latina, and White women who gave birth during the study period. A difference-in-differences (DID) analysis of Black vs White disparities in VPTB or PTB in a pandemic cohort was compared with a prepandemic cohort by using electronic medical records obtained from 2 hospitals in New York City. Exposures: Women who delivered from March 28 to July 31, 2020, were considered the pandemic cohort, and women who delivered from March 28 to July 31, 2019, were considered the prepandemic cohort. Reverse transcription-polymerase chain reaction tests for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were performed using samples obtained via nasopharyngeal swab at the time of admission. Main Outcomes and Measures: Clinical estimates of gestational age were used to calculate VPTB (<32 weeks) and PTB (<37 weeks). Log binomial regression was performed to estimate Black vs White risk differences, pandemic cohort vs prepandemic cohort risk difference, and an interaction term representing the DID estimator. Covariate-adjusted models included age, insurance, prepregnancy body mass index, and parity. Results: Of 3834 women in the pandemic cohort, 492 (12.8%) self-identified as Black, 678 (17.7%) as Latina, 2012 (52.5%) as White, 408 (10.6%) as Asian, and 244 (6.4%) as other or unspecified race/ethnicity, with approximately half the women 25 to 34 years of age. The prepandemic cohort comprised 4192 women with similar sociodemographic characteristics. In the prepandemic cohort, VPTB risk was 4.4% (20 of 451) and PTB risk was 14.4% (65 of 451) among Black infants compared with 0.8% (17 of 2188) VPTB risk and 7.1% (156 of 2188) PTB risk among White infants. In the pandemic cohort, VPTB risk was 4.3% (21 of 491) and PTB risk was 13.2% (65 of 491) among Black infants compared with 0.5% (10 of 1994) VPTB risk and 7.0% (240 of 1994) PTB risk among White infants. The DID estimators indicated that no increase in Black vs White disparities were found (DID estimator for VPTB, 0.1 additional cases per 100 [95% CI, -2.5 to 2.8]; DID estimator for PTB, 1.1 fewer case per 100 [95% CI, -5.8 to 3.6]). The results were comparable in covariate-adjusted models when limiting the population to women who tested negative for SARS-CoV-2. No change was detected in Latina vs White PTB disparities during the pandemic. Conclusions and Relevance: In this cross-sectional study of women who gave birth in New York City during the COVID-19 pandemic, no evidence was found for increased racial/ethnic disparities in PTB, among women who tested positive or tested negative for SARS-CoV-2.

Perspectives on Race and Medicine in the NICU.

Current data regarding racial and ethnic disparities in health outcomes of newborns requiring care in an NICU reveal significant differences in quality and access to care that disproportionally affects infants of color, particularly African American infants. These inequalities result in an increased infant mortality rate for Black children and higher preterm birth rates, as well as an increase in deaths due to low birth weight and decreased gestational age. Concurrently, there is emerging research exploring the role of diversity and adequate representation among medical providers in patient outcomes in Black communities. In this editorial, we present commentaries from a medical student, a neonatologist, and a parent of former NICU patients to further explore race in the NICU from different perspectives and understand what can be learned from their experiences about these systemic issues and why representation is a critical component of successful change.

Preterm disparities between foreign and Swedish born mothers depend on the method used to estimate gestational age. A Swedish population-based register study.

This study aims to examine whether disparities in gestational age outcomes between foreign and Swedish-born mothers are contingent on the measure used to estimate gestational age and, if so, to identify which maternal factors are associated with the discrepancy. Using population register data, we studied all singleton live births in Sweden from 1992-2012 (n = 1,317,265). Multinomial logistic regression was performed to compare gestational age outcomes classified into very (<32 weeks) and late preterm (32-36 weeks), term and post-term derived from the last menstrual period (LMP) and ultrasound estimates in foreign- and Swedish-born women. Compared to Swedish-born women, foreign-born women had similar odds of very preterm birth (OR: 0.98 [95% CI: 0.98, 1.01]) and lower odds of moderately preterm birth (OR: 0.95 [95% CI: 0.92, 0.98]) based on ultrasound, while higher risks based on LMP (respectively, OR: 1.10 [95% CI: 1.07, 1.14] and 1.09 [95% CI: 1.06, 1.13]). Conclusions on disparities in gestational age-related outcomes by mother's country of origin depend on the method used to estimate gestational age. Except for very preterm, foreign-born women had a health advantage when gestational age is based on ultrasound, but a health disadvantage when based on LMP. Studies assessing disparities in very preterm birth by migration status are not affected by the estimation method but caution should be taken when interpreting disparities in moderately preterm and preterm birth rates.

Cervical length distribution and other sonographic ancillary findings of singleton nulliparous patients at midgestation.

BACKGROUND: Short cervix at midgestation, the presence of intraamniotic debris, and cervical funneling are risk factors for preterm birth; however, cervical length measurements and cutoffs are not well documented among pregnant patients of different gestational ages and self-reported races and ethnicities. OBJECTIVE: This study aimed to describe the distribution of cervical length and frequency of funneling and debris at midgestation in nulliparous women by gestational age and race/ethnicity. STUDY DESIGN: This secondary analysis of screening data from a multicenter treatment trial of singleton nulliparous patients with short cervix was conducted at 14 geographically distributed, university-affiliated medical centers in the United States. Singleton nulliparous patients with no known risk factors for preterm birth were screened for trial participation and asked to undergo a transvaginal ultrasound to measure cervical length by a certified sonographer. The distribution of cervical length and the frequency of funneling and debris were assessed for each gestational age week (16-22 weeks) and stratified by self-reported race and ethnicity, which for this study were categorized as White, Black, Hispanic, and other. Patients enrolled in the randomized trial were excluded from this analysis. RESULTS: A total of 12,407 nulliparous patients were included in this analysis. The racial or ethnic distribution of the study participants was as follows: White, 41.6%; Black, 29.6%; Hispanic, 24.2%; and others, 4.6%. The 10th percentile cervical length for the entire cohort was 31.1 mm and, when stratified by race and ethnicity, 31.9 mm for White, 30.2 mm for Black, 31.4 mm for Hispanic, and 31.2 mm for patients of other race and ethnicity (P<.001). At each gestational age, the cervical length corresponding to the tenth percentile was shorter in Black patients. The 25 mm value commonly used to define a short cervix and thought to represent the 10th percentile ranged from 1.3% to 5.4% across gestational age weeks and 1.0% to 3.8% across race and ethnicity groups. Black patients had the highest rate of funneling (2.6%), whereas Hispanic and Black patients had higher rates of intraamniotic debris than White and other patients (P<.001). CONCLUSION: Black patients had shorter cervical length and higher rates of debris and funneling than White patients. The racial and ethnic disparities in sonographic midtrimester cervical findings may provide insight into the racial disparity in preterm birth rates in the United States.

Racial inequality in perinatal outcomes in two Brazilian birth cohorts.

This study aimed to estimate and compare racial inequality in low birth weight (LBW), preterm birth (PTB), and intrauterine growth restriction (IUGR) in two Brazilian birth cohorts. This was a cross-sectional study nested within two birth cohorts in Ribeirão Preto (RP) and São Luís (SL), whose mothers were interviewed from January to December 2010. In all, 7430 (RP) and 4995 (SL) mothers were interviewed. The maternal skin color was the exposure variable. Associations were adjusted for socioeconomic and biological covariates: maternal education, per capita family income, family economic classification, household head occupation, maternal age, parity, marital status, prenatal care, type of delivery, maternal pre-pregnancy BMI, hypertension, hypertension during pregnancy, and smoking during pregnancy collected from questionnaires applied at birth. Statistical analysis was done with the chi-squared test and logistic regression. In RP, newborns from mothers with black skin color had a higher risk of LBW and IUGR, even after adjusting for socioeconomic and biological variables (P<0.001). In SL, skin color was not a risk factor for LBW (P=0.859), PTB (P=0.220), and IUGR (P=0.062), before or after adjustment for socioeconomic and biological variables. The detection of racial inequality in these perinatal outcomes only in the RP cohort after adjustment for socioeconomic and biological factors may be reflecting the existence of racial discrimination in the RP society. In contrast, the greater miscegenation present in São Luís may be reflecting less racial discrimination of black and brown women in this city.

Understanding Racial Disparities of Preterm Birth Through the Placenta.

The racial disparity associated with preterm birth is a public health concern in the United States. The placenta is the principal metabolic, respiratory, and endocrine organ of the fetus and a key route by which environmental exposures are transmitted from mother to offspring. Available at every delivery, it may serve as a marker of differences in prenatal exposures that manifest differently by race. Recently, we described differences in placental pathology between African-American and White preterm births: the prevalence of chronic inflammation was higher among African-American women's placentas compared with those of White women. Similarly, racial differences have been shown in placental malperfusion and placental weight. Social determinants such as poverty and stress from discrimination have been implicated in racial disparities in preterm birth. To date, however, the underlying biological mechanisms, whether through inflammatory, oxidative stress, or other pathways involving epigenetic programming, remain largely unknown. The placenta, complemented by maternal and umbilical cord blood biomarkers, may provide important information on the perinatal environment that explains the origins of racial disparities in preterm birth rates and subsequent health outcomes. This article reviews existing literature and current research gaps. Opportunities are discussed for future placental research that may reveal novel mechanisms leading to the development of new approaches in the prevention and management of preterm birth and its outcomes.