Division of Cardiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
Department of Internal Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
JAMA Pediatr. 2024 Jan 1;178(1):65-72. doi: 10.1001/jamapediatrics.2023.4907.
Preterm birth is a major contributor to neonatal morbidity and mortality, and considerable differences exist in rates of preterm birth among maternal racial and ethnic groups. Emerging evidence suggests pregnant individuals born outside the US have fewer obstetric complications than those born in the US, but the intersection of maternal nativity with race and ethnicity for preterm birth is not well studied.
To determine if there is an association between maternal nativity and preterm birth rates among nulliparous individuals, and whether that association differs by self-reported race and ethnicity of the pregnant individual.
DESIGN, SETTING, AND PARTICIPANTS: This was a nationwide, cross-sectional study conducted using National Center for Health Statistics birth registration records for 8 590 988 nulliparous individuals aged 15 to 44 years with singleton live births in the US from 2014 to 2019. Data were analyzed from March to May 2022.
Maternal nativity (non-US-born compared with US-born individuals as the reference, wherein US-born was defined as born within 1 of the 50 US states or Washington, DC) in the overall sample and stratified by self-reported ethnicity and race, including non-Hispanic Asian and disaggregated Asian subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, Pacific Islander, Vietnamese, and other Asian), non-Hispanic Black, Hispanic and disaggregated Hispanic subgroups (Cuban, Mexican, Puerto Rican, and other Hispanic), and non-Hispanic White.
The primary outcome was preterm birth (<37 weeks of gestation) and the secondary outcome was very preterm birth (<32 weeks of gestation).
Of 8 590 988 pregnant individuals included (mean [SD] age at delivery, 28.3 [5.8] years in non-US-born individuals and 26.2 [5.7] years in US-born individuals; 159 497 [2.3%] US-born and 552 938 [31.2%] non-US-born individuals self-identified as Asian or Pacific Islander, 1 050 367 [15.4%] US-born and 178 898 [10.1%] non-US-born individuals were non-Hispanic Black, 1 100 337 [16.1%] US-born and 711 699 [40.2%] non-US-born individuals were of Hispanic origin, and 4 512 294 [66.1%] US-born and 328 205 [18.5%] non-US-born individuals were non-Hispanic White), age-standardized rates of preterm birth were lower among non-US-born individuals compared with US-born individuals (10.2%; 95% CI, 10.2-10.3 vs 10.9%; 95% CI, 10.9-11.0) with an adjusted odds ratio (aOR) of 0.90 (95% CI, 0.89-0.90). The greatest relative difference was observed among Japanese individuals (aOR, 0.69; 95% CI, 0.60-0.79) and non-Hispanic Black individuals (aOR, 0.74; 0.73-0.76) individuals. Non-US-born Pacific Islander individuals experienced higher preterm birth rates compared with US-born Pacific Islander individuals (aOR, 1.15; 95% CI, 1.04-1.27). Puerto Rican individuals born in Puerto Rico compared with those born in US states or Washington, DC, also had higher preterm birth rates (aOR, 1.07; 95% CI, 1.03-1.12).
Overall preterm birth rates were lower among non-US-born individuals compared with US-born individuals. However, there was substantial heterogeneity in preterm birth rates across maternal racial and ethnic groups, particularly among disaggregated Asian and Hispanic subgroups.
早产是导致新生儿发病率和死亡率的主要原因，不同种族和族裔的产妇之间早产率存在相当大的差异。新出现的证据表明，与在美国出生的孕妇相比，在美国境外出生的孕妇分娩时并发症较少，但产妇出生地与种族和族裔对早产的交叉影响尚未得到很好的研究。
确定在初产妇中，产妇出生地与早产率之间是否存在关联，以及这种关联是否因孕妇自报的种族和族裔而异。
设计、地点和参与者：这是一项全国性的、横断面研究，使用美国国家卫生统计中心 2014 年至 2019 年期间的出生登记记录，对 8590988 名年龄在 15 至 44 岁之间、单胎活产的初产妇进行了分析。数据于 2022 年 3 月至 5 月进行了分析。
产妇出生地（非美国出生与美国出生相比，美国出生定义为在 50 个美国州或华盛顿特区之一出生）在总体样本中以及按自报种族和族裔分层，包括非西班牙裔亚裔和亚裔亚组（印度裔、华裔、菲律宾裔、日裔、韩裔、太平洋岛裔、越裔和其他亚裔）、非西班牙裔黑人和西班牙裔和西班牙裔亚组（古巴裔、墨西哥裔、波多黎各裔和其他西班牙裔）以及非西班牙裔白人和非西班牙裔白人和西班牙裔亚组（波多黎各裔、墨西哥裔、波多黎各裔和其他西班牙裔）。
主要结局是早产（<37 周），次要结局是极早产（<32 周）。
在纳入的 8590988 名孕妇中（分娩时的平均[标准差]年龄，非美国出生者为 28.3[5.8]岁，美国出生者为 26.2[5.7]岁；159497[2.3%]名美国出生者和 552938[31.2%]名非美国出生者自报为亚裔或太平洋岛民，1050367[15.4%]名美国出生者和 178898[10.1%]名非美国出生者是非西班牙裔黑人，1100337[16.1%]名美国出生者和 711699[40.2%]名非美国出生者是西班牙裔，4512294[66.1%]名美国出生者和 328205[18.5%]名非美国出生者是非西班牙裔白人），非美国出生者的早产率标准化年龄低于美国出生者（10.2%；95%置信区间，10.2-10.3 与 10.9%；95%置信区间，10.9-11.0），调整后的优势比（aOR）为 0.90（95%置信区间，0.89-0.90）。最大的相对差异见于日本个体（aOR，0.69；95%置信区间，0.60-0.79）和非西班牙裔黑人个体（aOR，0.74；95%置信区间，0.73-0.76）。与美国出生的太平洋岛民相比，非美国出生的太平洋岛民的早产率更高（aOR，1.15；95%置信区间，1.04-1.27）。与在美国州或华盛顿特区出生的人相比，在波多黎各出生的波多黎各个体的早产率也更高（aOR，1.07；95%置信区间，1.03-1.12）。
与美国出生的个体相比，非美国出生的个体总体早产率较低。然而，在产妇的种族和族裔群体中，早产率存在很大的异质性，特别是在亚裔和西班牙裔亚组中。
