Maternal and Infant Health Outcomes in US-Born and Non-US-Born Black Pregnant People in the US

Abstract

Importance: With disparate Black maternal health outcomes in the US and a steadily expanding non-US-born Black population, it is beneficial to investigate Black maternal health outcomes by country of origin.

Objective: To compare the prevalence of maternal morbidity and infant birth outcomes between US-born and non-US-born Black populations in the US.

Design, setting, and participants: This cross-sectional study included all registered hospital births in the US from the 2021 National Vital Statistics Systems (NVSS) Natality Data. Eligible patients identified as Black, excluding those who were younger than 15 years, gave birth to twins or multiple infants, gave birth outside of a hospital, or were missing data for maternal morbidity, nativity, or study covariates.

Exposures: Maternal birthplace, characterized as born within the US or born outside of the US.

Main outcomes and measures: Five maternal morbidities (ie, maternal transfusion, perineal laceration, ruptured uterus, unplanned hysterectomy, admission to intensive care unit) and two birth outcomes (low birthweight, preterm birth). Logistic regression analyses were utilized to calculate the associations of maternal morbidity and adverse birth outcome with maternal birthplace.

Results: Of a total 3 669 928 registered births in the US in 2021, 499 409 births to mothers who identified as Black were included in analysis; the majority of individuals were aged 20 to 24 years (117 173 [23.5%]), 25 to 29 years (142 890 [28.6%]), or 30 to 34 years (123 485 [24.7%]). Maternal birthplace in the US was associated with a decreased odds of experiencing any maternal morbidity (4411 of 403 822 births [1.1%]) compared with Black people born outside of the US (1593 of 95 587 births [1.7%]) (aOR, 0.67; 95% CI, 0.62-0.71). US-born Black people were significantly less likely to experience 3 of 5 maternal morbidities compared with non-US-born Black people: maternal transfusion (aOR, 0.87; 95% CI, 0.78-0.97), perineal laceration (aOR, 0.43; 95% CI, 0.39-0.48), and ruptured uterus (aOR, 0.63; 95% CI, 0.45-0.89). US-born Black people also had a nonsignificant decrease in odds for unplanned hysterectomy (aOR, 0.77; 95% CI, 0.56-1.05) and admission to intensive care unit (aOR, 0.92; 95% CI, 0.79-1.07). However, they were at increased odds of experiencing key adverse infant health outcomes, including low birthweight (aOR, 1.62; 95% CI, 1.58-1.67) and preterm birth (aOR, 1.51; 95% CI, 1.47-1.55).

Conclusions and relevance: In this cross-sectional study, significant differences were observed in odds of maternal morbidity and birth outcomes by maternal birthplace within the Black pregnant population in the US. This suggests the need for increased assessment of nativity in Black maternal health research and specific strategies to reduce morbidity for non-US-born populations.

Figure 1.. Directed Acyclic Graph (DAG) of Association Between Mother’s Birth Country, Maternal Morbidity, and Covariates

US-born or non–US-born indicates the exposure, and maternal morbidity the outcome; orange dots, ancestor of the exposure and outcome (covariate); blue dots, ancestor of the outcome. BMI indicates body mass index (calculated as weight in kilograms divided by height in meters squared).

Figure 2.. Analytical Sample Selection Process

NVSS indicates National Vital Statistics Systems.