Factor Structure for Chronic Stress Before and During Pregnancy by Racial/Ethnic Group

Black-white differences in chronic stress exposures to predict preterm birth: interpretable, race/ethnicity-specific machine learning model

BACKGROUND

Differential exposure to chronic stressors by race/ethnicity may help explain Black-White inequalities in rates of preterm birth. However, researchers have not investigated the cumulative, interactive, and population-specific nature of chronic stressor exposures and their possible nonlinear associations with preterm birth. Models capable of computing such high-dimensional associations that could differ by race/ethnicity are needed. We developed machine learning models of chronic stressors to both predict preterm birth more accurately and identify chronic stressors and other risk factors driving preterm birth risk among non-Hispanic Black and non-Hispanic White pregnant women.

METHODS

Multivariate Adaptive Regression Splines (MARS) models were developed for preterm birth prediction for non-Hispanic Black, non-Hispanic White, and combined study samples derived from the CDC's Pregnancy Risk Assessment Monitoring System data (2012-2017). For each sample population, MARS models were trained and tested using 5-fold cross-validation. For each population, the Area Under the ROC Curve (AUC) was used to evaluate model performance, and variable importance for preterm birth prediction was computed.

RESULTS

Among 81,892 non-Hispanic Black and 277,963 non-Hispanic White live births (weighted sample), the best-performing MARS models showed high accuracy (AUC: 0.754-0.765) and similar-or-better performance for race/ethnicity-specific models compared to the combined model. The number of prenatal care visits, premature rupture of membrane, and medical conditions were more important than other variables in predicting preterm birth across the populations. Chronic stressors (e.g., low maternal education and intimate partner violence) and their correlates predicted preterm birth only for non-Hispanic Black women.

CONCLUSIONS

Our study findings reinforce that such mid or upstream determinants of health as chronic stressors should be targeted to reduce excess preterm birth risk among non-Hispanic Black women and ultimately narrow the persistent Black-White gap in preterm birth in the U.S.

Prenatal stress and hair cortisol in a sample of Latina women

BACKGROUND

Stress during pregnancy adversely impacts maternal and infant health. Dysregulation of the hypothalamic pituitary axis is a mediator of the relationship between stress and health. Evidence supporting an association between prenatal chronic stress and cortisol is limited, and the majority of research published has been conducted amongst White participants, who experience less chronic stress than people of color.

AIM

This study investigated associations between various measures of prenatal stress and hair cortisol concentrations which is a biomarker of the integrated stress response in a sample of Latina participants during the third trimester of pregnancy.

METHOD

Pregnant women (n=45) were surveyed with scales measuring chronic stress, perceived stress, pregnancy-related and pregnancy-specific anxiety. Hair samples were collected as an objective neuroendocrine measure of chronic stress. Linear regression analyses were performed to assess associations between stress measures and hair cortisol. Pre-pregnancy BMI, smoking during pregnancy, and steroid use during pregnancy were used as covariates in adjusted models.

RESULTS

Chronic stress, operationalized as maternal reports of neighborhood/housing strain, daily activities and relationship strain, discrimination, and financial strain, was significantly associated with higher hair cortisol concentrations. No significant associations were found between hair cortisol and perceived stress, pregnancy-related anxiety, nor pregnancy-specific anxiety in adjusted models.

CONCLUSION

Chronic stress may be a more robust correlate of physiological stress, as measured by hair cortisol in pregnancy, than other common measures of prenatal stress and anxiety.

Different maternal age patterns of preterm birth: Interplay of race/ethnicity, chronic stress, and marital status

The aim of this study was to examine whether the preterm birth (PTB) risks according to maternal age is altered by a woman's marital status and chronic stress among non-Hispanic (N-H) White, N-H Black, Hispanic, and Asian women. This researcher analyzed the Pregnancy Risk Assessment Monitoring System data for New York City and Washington State linked with the birth certificates for 2004-2007. The sample included 6344 singleton live births without birth defects to women aged 18 years or older identified as N-H White, N-H Black, Hispanic, or Asian. The outcome was PTB. Maternal age-specific PTB rates were calculated according to race/ethnicity, marital status, and chronic stress. Linear trends of PTB rates with maternal age were evaluated by the Mantel-Haenszel χ² test. Marriage had a protective effect against PTB at advancing maternal age across racial/ethnic groups. The health benefit of marriage was strong, particularly among the married N-H Black and Asian women, manifested as a maternal age-related decrease in the PTB rate (reverse-weathering). In contrast, women not married showed a maternal age-related increase in the PTB rate (weathering) across the racial/ethnic groups. Under higher chronic stress, married women generally experienced less weathering about PTB. These patterns were observed with noticeable racial/ethnic variations. Acknowledging the different dynamics among maternal age, marital status, and chronic stress by race/ethnicity could help shed light on the psychosocial mechanisms underlying the racial/ethnic inequalities in PTB in the United States. To that end, future studies should use more nuanced measurements of paternal support and chronic stress.

Maternal Age Patterns of Preterm Birth: Exploring the Moderating Roles of Chronic Stress and Race/Ethnicity

BACKGROUND

Despite the suggested contribution of cumulative chronic stress to the racial/ethnic disparities in preterm birth (PTB), it is unclear how chronic stress, maternal age, and race/ethnicity are linked underlying PTB.

PURPOSE

We investigated the moderating effect of chronic stress on the maternal age-PTB association among non-Hispanic (N-H) White, N-H Black, Hispanic, and Asian women.

METHODS

We analyzed the Washington State's Pregnancy Risk Assessment Monitoring System data linked with birth certificates. The sample included women aged 18 years or older who birthed the first, singleton baby without birth defects. Chronic stress was measured by race/ethnicity-specific chronic stress indices. A maternal age-chronic stress interaction was modeled to predict PTB by logistic regression stratified by race/ethnicity. In subanalysis, the moderating role of racism was investigated in the maternal age-chronic stress interaction among three minority groups combined.

RESULTS

Women's maternal age trajectory of PTB varied by their race/ethnicity and chronic stress level. N-H White and N-H Black women showed a steeper maternal age-related increase in PTB (weathering) under higher chronic stress, indicating a chronic stress' cumulative effect with maternal age. Besides, the extent of weathering was amplified by racism on top of chronic stress, particularly among N-H Black women.

CONCLUSIONS

These results show that both chronic stress and racism may develop accelerated PTB risk among minority women. Future research should use more objective and accurate chronic stress measures to ascertain the complex relationships among chronic stress, racial discrimination, and maternal age underlying the racial/ethnic differentials in PTB.