There is heterogeneity for the immigrant paradox of preterm birth between nativity, ethnicity, and racial identities, according to a recent study published in JAMA Network Open.
Takeaways
- Racial and ethnic disparities persist in preterm birth rates, with non-Hispanic Black individuals experiencing a 50% higher rate compared to non-Hispanic White individuals, highlighting ongoing health inequities.
- Maternal nativity, including factors such as citizenship and acculturation, also plays a significant role in preterm birth risk, suggesting the importance of considering immigrant experiences in health care interventions.
- The study included over 34 million singleton live births, providing robust data to analyze the impact of nativity, ethnicity, and race on preterm birth outcomes.
- US-born individuals generally had higher preterm birth rates across racial and ethnic groups compared to non-US-born counterparts, indicating potential environmental or health care system factors at play.
- Findings reveal complexities in the immigrant paradox of preterm birth, emphasizing the need for intersectional approaches to address structural discrimination and improve maternal and child health outcomes.
Approximately 1 in 10 US births are impacted by preterm birth, with a rate of 10.5% reported in 2021. Preterm birth is associated with increased risks of mortality and lifelong impairments.
Additionally, there are racial and ethnic disparities related to preterm birth, with a 50% higher rate among non-Hispanic Black birthing individuals than non-Hispanic White. Other groups with disparities in preterm births include American Indian and Pacific Islander. This indicates a need to monitor population patterns.
Nativity, which impacts citizenship, preferred language, acculturation, interpersonal discrimination exposure, and experience with xenophobia, may also impact preterm birth. As intersecting identities may conflict, preterm birth risk could be impacted by a multitude of structural and individual factors.
To determine the impact of maternal nativity, ethnicity, and race on preterm birth, investigators conducted a retrospective national cohort study. In-hospital singleton live births between January 1, 2009, and December 31, 2018, recorded in the National Vital Statistics System were included in the analysis.
Exclusion criteria included missing maternal characteristics, missing or outlier gestational age or birthweight, and multiples. US birth certificates were evaluated for data on race, ethnicity, and nativity, and the term “minoritized” was used instead of “minorities.”
Participants self-reported their country of birth to determine if they were US-born or non-US-born. Those born in US territories were considered US-born as well as those born in the US mainland. Patients identifying as Hispanic were categorized into the same group encompassing all races.
Preterm birth, defined as birth under 37 weeks of gestation, was reported as the primary outcome of the analysis. Data such as ultrasonography and last menstrual period was used to determine gestational age. Preterm birth categories included extremely preterm at under 29 weeks, moderately preterm at 29 to 33 weeks, and late preterm at 34 to 36 weeks.
Covariates included age, education level, insurance type, diabetes and hypertension, prenatal care, and tobacco use. Congenital anomalies in newborns were also reported as a binary variable.
There were 34,468,901 singleton live births included in the analysis, with a mean maternal age of 28 years. US-born individuals often delivered at a younger age.
Not having a high school diploma was more often reported in non-US-born Hispanic, Asian, and Pacific Islander birthing people compared to US-born populations. A lack of Medicaid or private insurance was reported by 19.8% of non-US-born Hispanic birthing people vs 10% of non-US-born White or Asian birthing people.
The highest preterm birth rate among US-born birthing people was reported among Black patients at 12.1%, while the lowest of 7.2% was reported among White patients. For non-US-born patients, the highest and lowest rates were 9.8% among Pacific Islander patients and 5.5% among White patients, respectively.
Higher preterm birth rates were reported among all US-born groups compared to their non-US-born counterparts. This was also reported for all rates of extremely preterm birth, and all rates of moderately and late preterm birth except for Pacific Islander birthing people.
A significant increase in preterm birth was also reported among all US-born groups compared to US-born White patients. When compared to US-born White patients, only non-US-born White and non-US-born Hispanic patients had a decreased risk of preterm birth, with relative risks of 0.85 and 0.98, respectively.
These results indicated heterogeneity for the immigrant paradox of preterm birth between nativity, ethnicity, and racial identities. Investigators recommended further research to evaluate how these factors together may be used to measure the impact of intersectional structural discrimination.
Reference
Barreto A, Formanowski B, Peña M, et al. Preterm birth risk and maternal nativity, ethnicity, and race. JAMA Netw Open. 2024;7(3):e243194. doi:10.1001/jamanetworkopen.2024.3194
