Objective

This study aims to compare preterm birth (PTB) risk and maternal factors associated with PTB among non-Hispanic White, Black, and mixed-race Black/White women in the United States.

Methods

In this study, we used U.S. birth certificate data from the 2017 National Vital Statistics System. We included live singleton births to women who self-identified as non-Hispanic White, Black, or mixed-race Black/White. PTB was defined as less than 37 weeks of gestation. We used logistic regression models to estimate the PTB odds ratios for Black and Black/White relative to White women, adjusted for maternal factors. We used logistic regression to estimate associations between PTB and maternal factors in race-stratified models.

Results

The sample included a total of 2,297,076 births in 2017 to White (n = 1,792,257), Black (n = 476,969), and Black/White (n = 27,850) women. The prevalence of PTB varied for Black (11.2%), Black/White (8.2%), and White (6.8%) women. The odds of PTB compared with White differed for Black (odds ratio, 1.51; 95% confidence interval, 1.49-1.53) and Black/White (odds ratio, 1.13; 95% confidence interval, 1.08-1.18) women after adjusting for maternal factors. The odds of PTB associated with maternal sociodemographic, prepregnancy, and gestational factors differed by maternal race.

Conclusions

Evaluation of PTB risk among White, Black, and Black/White women revealed distinct associations between PTB and maternal factors for Black/White women. This study highlights the need for research assessing the relationships between social risk factors such as colorism and racism and the outcome of PTB, and it provides evidence that may inform more targeted PTB prevention among Black/White and Black women.