Abstract
The purpose of this study was to investigate the associations between multilevel racism and gestational age at birth among nulliparous women. We conducted a secondary analysis of data of the nuMoM2b Study (2010–2013) to examine the associations between individual- and structural-level experiences of racism and discrimination and gestational age at birth among nulliparous women (n = 9148) at eight sites across the U.S. Measures included the individual Experiences of Discrimination (EOD) scale and the Index of Concentration at the Extremes (ICE) to measure structural racism. After adjustment, we observed a significant individual and structural racism interaction on gestational length (p = 0.012). In subgroup analyses, we found that among those with high EOD scores, women who were from households concentrated in the more privileged group had significantly longer gestations (β = 1.27, 95% CI: 0.48, 2.06). Women who reported higher EOD scores and more economic privilege had longer gestations, demonstrating the moderating effect of ICE as a measure of structural racism. In conclusion, ICE may represent a modifiable factor in the prevention of adverse birth outcomes in nulliparas.
Supplementary Information
The online version contains supplementary material available at 10.1007/s11524-024-00889-1.
Keywords: Discrimination, Gestational age, Black Americans
Introduction
Preterm birth is a primary contributor to perinatal morbidity and mortality, and is experienced disproportionately by Black women in the United States [1, 2]. Maternal stress, including experiences of racism, has been hypothesized as a root cause of perinatal health inequities in the United States (U.S.) [3]. Racism is a pervasive issue that can manifest in various forms such as individual bias, institutional practices, and societal norms, and it has serious and lasting impacts on individuals’ health and well-being [4, 5]. Personally mediated, or individual-level racism, is defined as differential assumptions about people and actions towards them based on race, while structural racism is defined as differential access to goods, services, and opportunities in society based on race [6]. The study of racism at multiple levels and its physiologic effects on pregnancy and birth outcomes has been identified as a means to reduce perinatal inequities [7]. Although there is a significant body of literature examining the effects of racism on perinatal outcomes, research that comprehensively conceptualizes and measures racism at multiple levels to inform areas for intervention remains limited.
The majority of studies on racism and preterm birth are conducted at the individual level. The earliest studies examining the association between racism and adverse birth outcomes date to the mid-1990s; however, methods varied and instruments to measure individual-level racial discrimination were just beginning to be developed [8, 9]. Instruments such as the Experiences of Discrimination [10] and the Everyday Discrimination Scale [11] were implemented in studies in the 2000s, revealing a positive relationship between racial discrimination and preterm birth [12]. A subsequent review of the literature began to promote a life course approach to studying this question, concluding that proximal measures of discrimination related to access to and quality of prenatal care, neighborhood characteristics, and employment were positively associated with adverse birth outcomes [4]. Overall findings were mixed, however, with the authors noting heterogeneity in measurement of perceived racism, sample sizes, and time period where discrimination was assessed [4]. A more recent comprehensive review of 60 studies primarily examining individual-level racism and preterm birth similarly found that study methods and definitions of racism varied, hindering progress in understanding this phenomenon [13].
Research on structural racism and preterm birth has focused largely on Black women, and employed measures representing structural inequity such as racial residential segregation, neighborhood disadvantage, and the Index of Concentration at the Extremes (ICE) [3, 13, 14]. This body of research studies has reported significant associations between excess policing [15], violence [16], neighborhood evictions [17], and incarceration [18] and adverse birth outcomes for Black women. However, the pervasive nature of structural racism has presented difficulty in its measurement and thus inconsistency in methodological approaches. A systematic review examining racial residential segregation and adverse birth outcomes reported an increased risk of preterm birth among Black mothers compared to White mothers [14]. Another recent review of studies examining individual (n = 17) and structural racism (n = 43) reported that neighborhood or environmental measures derived from publicly available data sources were most commonly used (e.g., the neighborhood deprivation index and ICE) [13]. The authors noted that inconsistent definitions of exposures and outcomes prevented comparisons across studies.
One of the barriers to establishing a gold standard of measuring structural racism is its multidimensional nature. Investigators have attempted to capture this through the development of indices that combine several dimensions of structural racism [19, 20]. However, no existing studies have accounted for multiple levels of racism or simultaneously considered individual and structural effects of racism on birth outcomes. Exposure to interpersonal experiences of racism may differ for individuals within geographic areas exposed to varying degrees of structural racism, and this may be particularly true during pregnancy.
Therefore, the purpose of this study was to examine the associations between individual- and structural-level experiences of racism and discrimination and gestational age at birth among women from the Nulliparous Pregnancy Outcomes Study: Monitoring mothers-to-be (nuMoM2b), a large, longitudinal study funded by the National Institutes of Health [21]. Our hypothesis was women with higher individual Experiences of Discrimination (EOD) scores and more disadvantage in one measure of structural racism would have shorter gestations than those with less exposure to racism.
Methods
We conducted a secondary analysis of data from the nuMoM2b study, a multicenter prospective cohort study of nulliparous pregnant women from 2010 to 2013. Study procedures have been previously described [21]. A convenience sample of women with singleton pregnancies between 6 and 13 weeks were recruited (N = 10,038) from eight academic medical centers to examine maternal, placental, and fetal development risk factors and adverse pregnancy outcomes. Data collection included participant interview, self-administered questionnaires, chart abstraction, clinical, and biological measures. Exclusion criteria for nuMoM2b included maternal age < 13 years of age, fetal malformation, pregnancy lasting < 20 weeks gestation, and planned termination.
Exposures
Individual Experiences of Discrimination
The Experiences of Discrimination (EOD) scale measures self-reported individual experiences of racism and discrimination in adults of all races and ethnicities from working class backgrounds, with high reliability (Cronbach’s alpha = 0.74) in diverse samples [22]. Respondents indicate (yes/no) if the situation has happened to them and provide the reason for the perceived discrimination. Participants in nuMoM2b completed these questions asking about discrimination related to race, ethnicity, and skin color during their second trimester study visit (between 16 + 0 and 21 + 6 weeks gestation). Although the EOD is a subjective measure, it is strongly associated with psychological distress, stress biomarkers, and disease outcomes [23–25]. Total responses can be examined both continuously and categorized as low (none of the situations), medium (1 or 2), or high (3 + of the situations) [22], or a dichotomous variable defined as low (0–2 of the situations) vs. high (3 + of the situations) levels [26]. In this study, we used the dichotomous version of the EOD measure, with low defined as scores < 3, and high as scores ≥ 3.
Structural Racism Measure
We used the income and racial polarization index (ICE) [27, 28] as our measure of structural racism. This was calculated: Income = (A − P) / T, where A = number of NH White households with income $100,000 or higher (privileged group); P = number of NH Black households with income < $25,000 (deprived group); T = total number of NH Black and NH White households by census tract. The range for this index is from − 1 (all households in deprived group) to 1 (all households in the privileged group).
As household income data are not part of the 2010 decennial census, we used household counts from the 2010 Census [29] and the relevant household income counts from the 2014 American Community Survey [30]. ICE was calculated using these combined data sources. This introduced a temporal discontinuity in the counts and so there are a small number of tracts for which ICE was outside of the standard bounds of the metric. We winsorized those data to the closest bounded extreme (negative extreme (− 1) and positive extreme (+ 1)) in order to retain the ICE measures that are outliers [31].
Race and Ethnicity
We included all participants with complete data on our exposures and outcomes (n = 9148). Race and ethnicity were assessed at the baseline interview. Participants indicated their identity as Non-Hispanic White, Non-Hispanic Black, Hispanic, American Indian, Asian, Native Hawaiian, multiracial, or “other.” We conceptualize race and ethnicity in this study as sociopolitical variables, not as biological variables.
Outcome
Gestational Age
Gestational age at birth was calculated as per the nuMoM2b study protocol. We used a combination of available variables, including last menstrual period, ultrasound, and chart abstraction data to determine the most accurate due date measured in weeks. Participants were excluded from the present analyses if their births occurred before 22 weeks gestation, as this is often used as the minimum age of fetal viability [32]. As the participants were primiparas, we did not expect large differences in preterm birth rates as a binary variable, thus, we focused on differences in continuous gestational age.
Covariates
We controlled for a number of covariates available in the nuMoM2b data related to individual-level differences in maternal characteristics. These include maternal age, education, smoking status, gestational hypertension, preeclampsia, and gestational diabetes.
Maternal Age
This was treated as a continuous variable and calculated by subtracting the date of baseline interview from self-reported date of birth.
For education, participants indicated the number of years of completed education at the baseline interview.
Smoking was coded as ever-smokers (yes/no) if indicated at the baseline interview that they smoked tobacco in the three months prior to pregnancy.
Descriptive statistics were calculated for individual predictor variables and the ICE structural racism measure to describe maternal sociodemographic characteristics. Our primary aim was to assess whether individual and structural racism measures were associated with gestational age at birth. We controlled for maternal age, education, smoking, gestational hypertension, preeclampsia, and gestational diabetes in adjusted models. We employed linear-mixed effects models, where study site was treated as a random effect to account for variability from different sites (between subjects). All analyses were performed in R, and we received Institutional Board Approval from Columbia University for the current analysis (AAAU0215).
Results
A total of 9148 participants contributed data to the present analysis. Participants self-identified as NH White (57.3%; n = 5244), NH Black (11.8%; n = 1082), Hispanic (15.6%; n = 1428), and Other races (15.2%; n = 1394). More than half (54.5%, n = 4638) of participants were between 20 and 29 years old, and nearly all participants had at least a high school education (Table 1). Approximately 17.6% smoked tobacco in the 3 months prior to pregnancy. On average, women gave birth at 38.7 weeks gestation and 8.6% (n = 783) had a preterm birth. Women reported an average of 0.48 lifetime racial discrimination experiences (SD = 1.1; range = 0–9), and 93.4% of participants (n = 8223) reported less than three experiences of discrimination on the EOD measure. The mean value for ICE measures was 0.13 (SD = 0.28), and 24.5% (n = 2240) resided in households concentrated in the deprived group (ICE < 0).
Table 1.
Participant characteristics for non-hispanic black, non-hispanic white, and hispanic women in the nulliparous pregnancy outcomes study: Mothers-to-be (nuMoM2b) study, 2010–2013 (n = 9148)
| Characteristic | Overall N = 91481 |
Non-hispanic white N = 52441 |
Non-hispanic black N = 10821 |
Hispanic N = 14281 |
Other N = 13941 |
|
|---|---|---|---|---|---|---|
| Maternal age | ||||||
| 10–19 | 884 (10.3%) | 258 (4.9%) | 285 (26.3%) | 250 (17.5%) | 91 (12.0%) | |
| 20–29 | 4638 (54.5%) | 2787 (53.1%) | 642 (59.3%) | 883 (61.8%) | 326 (43.1%) | |
| 30–39 | 2868 (33.7%) | 2120 (40.4%) | 143 (13.2%) | 282 (19.7%) | 323 (42.7%) | |
| 40–49 | 119 (1.4%) | 79 (1.5%) | 12 (1.1%) | 13 (0.9%) | 15 (1.9%) | |
| Missing | 639 | 0 | 0 | 0 | 639 | |
| Mean (SD) | 26.99 (5.6) | 28.17 (5.1) | 23.42 (5.3) | 24.81 (5.5) | 27.98 (6.0) | |
| Education | ||||||
| Less than HS grad | 643 (7.5%) | 200 (3.8%) | 186 (17.1%) | 190 (13.3%) | 67 (8.9%) | |
| HS grad or GED | 995 (11.7%) | 388 (7.4%) | 277 (25.6%) | 265 (18.6%) | 65 (8.6%) | |
| Some college | 1664 (19.5%) | 782 (14.9%) | 323 (29.8%) | 430 (30.2%) | 129 (17.1%) | |
| Assoc/Tech degree | 868 (10.2%) | 540 (10.3%) | 111 (10.2%) | 157 (11.0%) | 60 (7.9%) | |
| Completed college | 2366 (27.8%) | 1809 (34.5%) | 113 (10.4%) | 239 (16.8%) | 205 (27.2%) | |
| Degree work beyond college | 1966 (23.1%) | 1525 (29.0%) | 72 (6.6%) | 142 (9.9%) | 227 (30.1%) | |
| Missing | 646 | 0 | 0 | 5 | 641 | |
| Smoked tobacco in the three months prior to pregnancy | ||||||
| No | 6999 (82.3%) | 4362 (83.2%) | 793 (73.2%) | 1227 (86.1%) | 617 (81.8%) | |
| Yes | 1504 (17.6%) | 880 (16.7%) | 289 (26.7%) | 198 (13.8%) | 137 (18.1%) | |
| Missing | 645 | 2 | 0 | 3 | 640 | |
| Site | ||||||
| Case Western Reserve University | 357 (3.9%) | 128 (2.4%) | 139 (12.8%) | 30 (2.1%) | 60 (4.3%) | |
| Columbia University | 1718 (18.7%) | 763 (14.5%) | 123 (11.3%) | 558 (39.0%) | 274 (19.6%) | |
| Indiana University | 744 (8.1%) | 386 (7.3%) | 200 (18.4%) | 69 (4.8%) | 89 (6.3%) | |
| Magee-Women’s Hospital | 1259 (13.7%) | 812 (15.4%) | 269 (24.8%) | 52 (3.6%) | 126 (9.0%) | |
| Northwestern University | 1359 (14.8%) | 948 (18.0%) | 50 (4.6%) | 99 (6.9%) | 262 (18.7%) | |
| University of California, Irvine | 743 (8.1%) | 210 (4.0%) | 54 (4.9%) | 331 (23.1%) | 148 (10.6%) | |
| University of Pennsylvania | 918 (10.0%) | 409 (7.8%) | 239 (22.0%) | 65 (4.5%) | 205 (14.7%) | |
| University of Utah | 2050 (22.4%) | 1588 (30.2%) | 8 (0.7%) | 224 (15.6%) | 230 (16.5%) | |
| Preterm birth (< 37 weeks) | ||||||
| No | 8365 (91.4%) | 4829 (92.0%) | 944 (87.2%) | 1319 (92.3%) | 1273 (91.3%) | |
| Yes | 783 (8.5%) | 415 (7.9%) | 138 (12.7%) | 109 (7.6%) | 121 (8.6%) | |
| Gestational age (weeks) at delivery, mean (s.d.) | 38.76 (2.3) | 38.87 (2.1) | 38.26 (3.0) | 38.78 (2.1) | 38.69 (2.3) | |
| Experiences of Discrimination (EOD) (range: (0,9)] | ||||||
| Low (EOD < | 8223 (93.4%) | 5033 (97.9%) | 832 (81.6%) | 1183 (89.7%) | 1175 (88.3%) | |
| High (EOD | 581 (6.6%) | 104 (2.0%) | 187 (18.3%) | 135 (10.2%) | 155 (11.6%) | |
| Missing | 344 | 107 | 63 | 110 | 64 | |
| Mean (SD) | 0.48 (1.1) | 0.22 (0.7) | 1.12 (1.6) | 0.71 (1.2) | 0.79 (1.3) | |
| Index of Concentration at the Extremes (ICE) (range: [− 1,1]) | ||||||
| Deprivation (ICE < 0) | 2240 (24.5%) | 481 (9.1%) | 823 (76.1%) | 561 (39.3%) | 375 (26.9%) | |
| Privilege (ICE ≥ 0) | 6902 (75.5%) | 4762 (90.8%) | 258 (23.8%) | 864 (60.6%) | 1018 (73.0%) | |
| Missing | 6 | 1 | 1 | 3 | 1 | |
| Mean (SD) | 0.13 (0.2) | 0.23 (0.2) | -0.20 (0.2) | 0.02 (0.2) | 0.13 (0.2) | |
1n (%); % was calculated using number of non-missing observation as denominator; Mean (SD) SD, standard deviation; Other group included all participants that are not Non-Hispanic White, Non-Hispanic Black, and Hispanic
In the unadjusted analysis (data not shown), we observed a significant relationship between ICE and gestational age effect regardless of whether EOD was high (β = 1.19, 95% CI: (0.45, 1.94); p-value = 0.002) or low (β = 0.39, 95% CI: (0.20, 0.57); p-value < 0.001). We note that the strength of this association did not differ significantly between the EOD high and low groups at the 0.05 significance level (p = 0.054).
Controlling for confounding variables, we observed a significant individual and structural racism interaction effect on gestational age at birth (β = 0.81, 95% CI: (0.18–1.45); p-value = 0.012) (Table 2). In the subgroup analyses, our data showed that among those with high EOD scores, women who were from households concentrated in the more privileged group had significantly longer gestations (β = 1.27, 95% CI: (0.48, 2.06); p-value = 0.002). However, among those with low EOD scores, there was no significant relationship between ICE and gestational age (β = 0.12, 95% CI: (− 0.08, 0.32); p-value = 0.249) (Table 3). This moderating relationship is also depicted in Fig. 1.
Table 2.
Adjusted models examining individual experiences of discrimination and structural racism on gestational age at birth
| Predictors | Estimates (95% CI)a | p |
|---|---|---|
| (Intercept) | 39.30 (39.00, 39.60) | < 0.001 |
| ICE | 0.15 (− 0.05, 0.36) | 0.137 |
| EOD (high) | − 0.10 (− 0.29, 0.09) | 0.306 |
| Maternal age | − 0.03 (− 0.04, 0.02) | < 0.001 |
| Education | ||
| HS grad or GED | 0.19 (− 0.03, 0.41) | 0.095 |
| Some college | 0.28 (0.07, 0.48) | 0.009 |
| Associate/tech degree | 0.36 (0.12, 0.59) | 0.004 |
| Completed college | 0.65 (0.43, 0.88) | < 0.001 |
| Degree beyond college | 0.68 (0.43, 0.92) | < 0.001 |
| Smoking | − 0.02 (− 0.15, 0.11) | 0.745 |
| Gestational hypertension | − 0.14 (− 0.30, 0.03) | 0.100 |
| Preeclampsia | − 1.87 (− 2.06, − 1.69) | < 0.001 |
| Gestational diabetes | − 0.54 (− 0.76, − 0.31) | < 0.001 |
| ICE * EOD (high) | 0.81 (0.18, 1.45) | 0.012 |
aCI, confidence interval; the CI was approximated using the Wald method
Table 3.
Stratified analysis of individual experiences of discrimination on gestational age
| Low EOD group (n = 7646) | High EOD group (n = 532) | |||
|---|---|---|---|---|
| Predictors | Estimates (95% CI) | p | Estimates (95% CI) | p |
| (Intercept) | 39.22 (38.91, 39.53) | < 0.001 | 40.15 (38.89, 41.41) | < 0.001 |
| ICE | 0.12 (− 0.08, 0.32) | 0.249 | 1.27 (0.48, 2.06) | 0.002 |
| Maternal age | − 0.03 (− 0.04, − 0.02) | < 0.001 | − 0.06 (− 0.10, − 0.01) | 0.013 |
| Education | ||||
| HS grad or GED | 0.24 (0.02, 0.46) | 0.036 | − 0.46 (− 1.48, 0.56) | 0.377 |
| Some college | 0.30 (0.08, 0.51) | 0.006 | 0.01 (− 0.94, 0.96) | 0.986 |
| Associate/tech degree | 0.39 (0.15, 0.64) | 0.002 | − 0.10 (− 1.17, 0.97) | 0.853 |
| Completed college | 0.67 (0.43, 0.90) | < 0.001 | 0.51 (− 0.53, 1.55) | 0.333 |
| Degree beyond college | 0.71 (0.46, 0.96) | < 0.001 | 0.32 (− 0.77, 1.42) | 0.563 |
| Smoking | − 0.06 (− 0.19, 0.07) | 0.384 | 0.35 (− 0.18, 0.87) | 0.198 |
| Gestational hypertension | − 0.11 (− 0.28, 0.05) | 0.185 | − 0.49 (− 1.28, 0.30) | 0.224 |
| Preeclampsia | − 1.92 (− 2.11, − 1.73) | < 0.001 | − 1.37 (− 2.19, − 0.56) | 0.001 |
| Gestational diabetes | − 0.58 (− 0.82, − 0.35) | < 0.001 | − 0.10 (− 0.99, 0.79) | 0.831 |
Fig. 1.
Individual experiences of discrimination moderate the association between structural racism and gestational age at birth. A significant relationship between ICE and gestational age was found with high EOD (p-value = 0.002), but not with low EOD (p-value = 0.249)
Sensitivity analyses were performed to assess the robustness of the main findings (Supplemental tables). We examined whether there were differences in the way EOD was categorized. The EOD by ICE interaction effect remained significant when a three-level categorized EOD (no, low, or high) was used in the model (p-value = 0.009). We show that the high EOD group had significant interaction effects with both no and low EOD groups, and that the direction was the same for both comparisons.
Discussion
In this analysis, we found that individual experiences of racial discrimination and income and racial polarization measured by the ICE index were significantly associated with gestational age at birth in a sample of nulliparous women in the U.S. We also found that EOD moderated the association between racialized residential segregation and gestational age at birth. Our findings are in line with previous studies examining associations between individual- and structural-level racism separately and adverse birth outcomes [3, 33, 34]. We extend previous work by examining the association between individual and structural racism together with gestational age, and by extending analyses to include a broader group of women, including Hispanic, Asian, Native American, Hawaiian, and other participants whose race and ethnicity were not reported.
We found a significant relationship between individual and structural racism and gestational age at birth only for those with higher EOD exposure living in privileged households. This reveals the potentially protective effects that improving racial residential segregation could have for women experiencing high levels of individual-level racism.
While individual- and structural-level racism are both known to be associated with poorer birth outcomes, there is minimal research on the interaction between the two. One previous study reported an association between ICE index and EOD among a cohort of Black women, though the impact on birth outcomes was not reported [33]. A prior analysis of the nuMoM2b cohort found that high EOD alone did not explain the increase in preterm birth or small for gestational age birth among NH Black women [35]. This indicates the importance of studying structural racism as a risk factor and further evaluating the interaction between individual- and structural-level racism and their impacts on maternal and infant health outcomes.
Public Health Implications
Shorter gestation is one of the most important predictors of infant health and mortality [36]. Our findings convey the complex role of individual and structural racism on inequalities in birth outcomes. Individual experiences with discrimination and increased levels of stress associated with these experiences have also been shown to have detrimental effects on birth outcomes [37]. The income and racialized residential segregation captured by the ICE measure demonstrated injustices within communities through systematic racism and discrimination which have been shown to contribute to persistent health inequities and disparities that continue to impact communities of minoritized women today [3, 5, 33]. Thus, examination of these measures is important as they are tied to potential interventions to resolve the health impacts of social inequalities and health disparities. More work is required to further examine the multidimensional nature of racism and its effects on gestational age and birth outcomes.
This study builds upon previous findings on racism and pregnancy outcomes by examining the multilevel impact of individual experiences of discrimination and structural racism. Our study also had limitations. We conducted a cross-sectional study, limiting our ability to account for changes in exposure to racism and segregation patterns over time. However, the results from this study offer a glimpse into the impact of racism and discrimination experiences on gestational age at birth. Future studies should examine the effects of exposure to individual and structural experiences of racism across the lifetime using longitudinal datasets. Such datasets will be available soon as nuMoM2b is continuing to follow the cohort as part of the National Heart, Lung, and Blood Institutes Heart Health Study (HHS). Secondly, it is important to note that the low percentage of NH Black, Hispanic, and other minoritized women in the study may limit the generalizability of the findings. In addition, our study is limited by incomplete data on the length of time the women resided in their neighborhoods, which is an important factor to consider since the impact of exposure to unfavorable socioeconomic conditions throughout the lifetime and even across generations may lead to racial disparities in preterm birth and other adverse birth outcomes [38–41]. Finally, the primiparous women in nuMoM2b were healthy, low-risk, and had the means and agreed to participate in an intensive, longitudinal study. These characteristics may not be representative of the larger populations, and underscore the need for more longitudinal studies in pregnancy that focus enrollment on NH Black and Hispanic women, with considerable heterogeneity within their own racial and ethnic groups to more accurately study—and identify—reasons for disparities in adverse birth outcomes.
We have shown that individual experiences of racial discrimination and income and racial polarization are significantly associated with gestational age at birth in a sample of nulliparous women in the U.S. Further research is needed, including improved conceptualization of multilevel racism in studies examining racial and ethnic disparities in adverse birth outcomes. These studies should include a greater representation of demographically heterogenous women to better understand this complex relationship.
Supplementary Information
Below is the link to the electronic supplementary material.
Acknowledgements
This work was funded by Columbia Population Research Center (CPRC) Seed Pilot Funds Program, Grant # P2CHD058486, from the National Institute of Child Health and Human Development (NICHD). This study was also supported by grant funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD U10 HD063036, U10 HD063072, U10 HD063047, U10 HD063037, U10 HD063041, U10 HD063020, U10 HD063046, U10 HD063048, and U10 HD063053) and the National Heart, Lung, and Blood Institute (U01 HL145358) with supplemental support from the Office of Behavioral and Social Sciences Research. In addition, support was provided by Clinical and Translational Science Institutes: UL1TR001108 and UL1TR000153. The funding sources were not involved in the conduct of this research study or in the preparation of the article.
Author Contribution
V. Barcelona conceived and supervised the analysis and led the writing. L. Chen and Y. Zhao conducted the statistical analyses. G. Samari, C. Monk, R. McNeil, A. Baccarelli, and R. Wapner contributed to revision and editing of the manuscript. R. McNeil contributed to analysis. R. Wapner was a PI of the original study.
Data Availability
Data from nuMoM2b are available through: NICHD DASH - Eunice Kennedy Shriver National Institute of Child Health and Human Development Data and Specimen Hub (nih.gov).
Footnotes
Publisher's Note
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
Data from nuMoM2b are available through: NICHD DASH - Eunice Kennedy Shriver National Institute of Child Health and Human Development Data and Specimen Hub (nih.gov).