The association between maternal and paternal race and preterm birth.

Non-Hispanic black maternal race is a known risk factor for preterm birth. However, the contribution of paternal race is not as well established. We sought to evaluate the risk of preterm birth among non-Hispanic black, non-Hispanic white, and mixed non-Hispanic black and non-Hispanic white dyads. This was a population-based cohort study of all live births in the United States from 2015 to 2017, using live birth records from the National Vital Statistics System. Singleton, nonanomalous infants whose live birth record included maternal and paternal self-reported race as either non-Hispanic white or non-Hispanic black were included. The primary outcome was preterm birth at <37 weeks' gestation; secondary outcomes included preterm birth at <34 and <28 weeks' gestation and delivery gestational age (as a continuous variable). Data were analyzed using chi-square, t test, analysis of variance, and logistic regression. A Kaplan-Meier survival curve was also generated. There were 11,809,599 live births during the study period; 4,008,622 births met the inclusion criteria. Of included births, 291,647 (7.3%) occurred at <37 weeks' gestation. Using the convention of maternal race first followed by paternal race, preterm birth at <37 weeks' gestation was most common among non-Hispanic black and non-Hispanic black dyads (n=70,987 [10.8%]), followed by non-Hispanic black and non-Hispanic white (n=3137 [9.5%]), non-Hispanic white and non-Hispanic black (n=9136 [8.3%]), and non-Hispanic white and non-Hispanic white dyads (n=209,387 [6.5%]; P<.001 for trend). Births at <34 weeks' (n=74,474) and <28 weeks' gestation (n=18,474) were also more common among non-Hispanic black and non-Hispanic black dyads. Specifically, 24,351 (3.7%) non-Hispanic black and non-Hispanic black, 1017 (3.1%) non-Hispanic black and non-Hispanic white, 2408 (2.2%) non-Hispanic white and non-Hispanic black, and 46,698 non-Hispanic white and non-Hispanic white dyads delivered at <34 weeks' gestation, and 7988 non-Hispanic black and non-Hispanic black (1.2%), 313 (1.0%) non-Hispanic black and non-Hispanic white, 584 (0.5%) non-Hispanic white and non-Hispanic black, and 9589 (0.3%) non-Hispanic white and non-Hispanic white dyads delivered at <28 weeks' gestation. Non-Hispanic white and non-Hispanic white dyads delivered at a mean 38.8± standard deviation of 1.7 weeks' gestation, although non-Hispanic white and non-Hispanic black, non-Hispanic black and non-Hispanic white, and non-Hispanic black and non-Hispanic black dyads delivered at 38.6±2.0, 38.5±2.3, and 38.3±2.4 weeks' gestation, respectively (P<.001). Adjusted odds ratios for the association between maternal or paternal race and preterm birth were highest for non-Hispanic black and non-Hispanic black dyads at each gestational age cutoff: adjusted odds ratio, 1.60 (95% confidence interval, 1.11-1.19) (<37 weeks' gestation); adjusted odds ratio, 2.47 (95% confidence interval, 2.41-2.53) (<34 weeks' gestation); and adjusted odds ratio, 4.22 (95% confidence interval, 4.04-4.41) (<28 weeks' gestation) compared with the non-Hispanic white referent group. Models adjusted for insurance status, chronic hypertension, tobacco use during pregnancy, history of previous preterm birth, and male fetus. In the Kaplan-Meier survival analysis, non-Hispanic black and non-Hispanic black dyads delivered the earliest across the range of delivery gestational ages compared with all other combinations of dyads. Non-Hispanic black paternal race is a risk factor for preterm birth and should be considered when evaluating maternal a priori risk of prematurity. Future research should investigate the mechanisms behind this finding, including determining the contribution of factors, such as racism, maternal and paternal genetics, and epigenetics to an individual's risk of preterm birth.

Green CA ，Johnson JD ，Vladutiu CJ ，Manuck TA ... -  《-》

Racial Disparities in Prematurity Persist among Women of High Socioeconomic Status.

Johnson JD ，Green CA ，Vladutiu CJ ，Manuck TA ... -  《-》

Preterm birth among pregnant women living in areas with high social vulnerability.

Communities and individuals widely vary in their resources and ability to respond to external stressors and insults. To identify vulnerable communities, the Centers for Disease Control and Prevention developed the Social Vulnerability Index, an integrated tool to assess community resources and preparedness; it is based on 15 factors and includes individual scores in the following 4 themes: socioeconomic status (theme 1), household composition and disability (theme 2), minority status and language (theme 3), and housing type and transportation (theme 4) and an overall composite score. Several Social Vulnerability Index components have been independently associated with an increased risk of preterm birth. We sought to investigate the association of the Social Vulnerability Index for each patient's residence during pregnancy, personal clinical risk factors, and preterm birth. This was a retrospective cohort study of women carrying nonanomalous singleton or twin gestations delivering at a large university health system from April 2014 to January 2020. Women at high risk of spontaneous and medically indicated preterm birth were assigned to a census tract based on their geocoded home address, and a Social Vulnerability Index score was assigned to each individual by linking each patient's home address at the census tract level. Higher scores indicate greater social vulnerability. The primary outcome was preterm birth at <37 weeks' gestation; secondary outcomes were preterm birth at <34 and <28 weeks' gestation and composite major neonatal morbidity before initial hospital discharge (death, intraventricular leukomalacia or intraventricular hemorrhage, necrotizing enterocolitis, or bronchopulmonary dysplasia). Data were analyzed using the chi-square test, t test, and backward stepwise logistic regression. In addition, because race is a social construct, we conducted regression models omitting Black race. For all regression models, independent variables with a P value of <.20 remained in the final models. Overall, 15,364 women met the inclusion criteria, of which 18.5%, 6.5%, 2.1% of women delivered at <37, <34, and <28 weeks' gestation, respectively, and 3.1% of neonates were diagnosed with major composite morbidity. Women delivering before term at <37, <34, and <28 weeks' gestation were more likely to live in an area with a higher overall Social Vulnerability Index and higher social vulnerability in each Social Vulnerability Index theme. In regression models, the adjusted odds ratio of preterm birth increased with increasing Social Vulnerability Index scores (across all themes and the composite value); these effects were the greatest at the earliest gestational ages (eg, for the composite Social Vulnerability Index: adjusted odds ratio of preterm birth at <37 weeks' gestation for models, including Black race, 1.32 [95% confidence interval, 1.14-1.53]; adjusted odds ratio at <34 weeks' gestation, 1.60 [95% confidence interval, 1.27-2.01]; adjusted odds ratio at <28 weeks' gestation, 2.21 [95% confidence interval, 1.50-3.25]; adjusted odds ratio for composite major neonatal morbidity, 2.30 [95% confidence interval, 1.67-3.17]). Similar trends were seen for each Social Vulnerability Index theme. In addition, an increased adjusted odds ratio of composite major neonatal morbidity was recognized for each Social Vulnerability Index theme. Results were similar when Black race was removed from the models. The Social Vulnerability Index is a valuable tool that may further identify communities and individuals at the highest risk of preterm birth and may enable clinicians to integrate information regarding the local home environment of their patients to further refine preterm birth risk assessment.

Givens M ，Teal EN ，Patel V ，Manuck TA ... -  《-》

Maternal race and intergenerational preterm birth recurrence.

Preterm birth is a complex disorder with a heritable genetic component. Studies of primarily White women born preterm show that they have an increased risk of subsequently delivering preterm. This risk of intergenerational preterm birth is poorly defined among Black women. Our objective was to evaluate and compare intergenerational preterm birth risk among non-Hispanic Black and non-Hispanic White mothers. This was a population-based retrospective cohort study, using the Virginia Intergenerational Linked Birth File. All non-Hispanic Black and non-Hispanic White mothers born in Virginia 1960 through 1996 who delivered their first live-born, nonanomalous, singleton infant ≥20 weeks from 2005 through 2009 were included. We assessed the overall gestational age distribution between non-Hispanic Black and White mothers born term and preterm (<37 weeks) and their infants born term and preterm (<37 weeks) using Cox regression and Kaplan-Meier survivor functions. Mothers were grouped by maternal gestational age at delivery (term, ≥37 completed weeks; late preterm birth, 34-36 weeks; and early preterm birth, <34 weeks). The primary outcomes were: (1) preterm birth among all eligible births; and (2) suspected spontaneous preterm birth among births to women with medical complications (eg, diabetes, hypertension, preeclampsia and thus higher risk for a medically indicated preterm birth). Multivariable logistic regression was used to estimate odds of preterm birth and spontaneous preterm birth by maternal race and maternal gestational age after adjusting for confounders including maternal education, maternal age, smoking, drug/alcohol use, and infant gender. Of 173,822 deliveries captured in the intergenerational birth cohort, 71,676 (41.2%) women met inclusion criteria for this study. Of the entire cohort, 30.0% (n = 21,467) were non-Hispanic Black and 70.0% were non-Hispanic White mothers. Compared to non-Hispanic White mothers, non-Hispanic Black mothers were more likely to have been born late preterm (6.8% vs 3.7%) or early preterm (2.8 vs 1.0%), P < .001. Non-Hispanic White mothers who were born (early or late) preterm were not at an increased risk of early or late preterm delivery compared to non-Hispanic White mothers born term. The risk of early preterm birth was most pronounced for Black mothers who were born early preterm (adjusted odds ratio, 3.26; 95% confidence interval, 1.77-6.02) compared to non-Hispanic White mothers. We found an intergenerational effect of preterm birth among non-Hispanic Black mothers but not non-Hispanic White mothers. Black mothers born <34 weeks carry the highest risk of delivering their first child very preterm. Future studies should elucidate the underlying pathways leading to this racial disparity.

Smid MC ，Lee JH ，Grant JH ，Miles G ，Stoddard GJ ，Chapman DA ，Manuck TA ... -  《-》

Preterm Birth Risk and Maternal Nativity, Ethnicity, and Race.

Barreto A ，Formanowski B ，Peña MM ，Salazar EG ，Handley SC ，Burris HH ，Ortiz R ，Lorch SA ，Montoya-Williams D ... -  《JAMA Network Open》