OBJECTIVE: 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.

EXPOSURES: 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.

MAIN OUTCOMES AND MEASURES: The primary outcome was preterm birth (<37 weeks of gestation) and the secondary outcome was very preterm birth (<32 weeks of gestation).

RESULTS: 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).

OBJECTIVE: To examine associations of HDP or GDM with offspring CVH in early adolescence.

STUDY DESIGN: This analysis used data from the prospective Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study from 2000 to 2006 and the HAPO Follow-Up Study from 2013 to 2016. This analysis included 3,317 mother-child dyads from 10 field centers, comprising 70.8% of HAPO Follow-Up Study participants. Those with pregestational diabetes and chronic hypertension were excluded. The exposures were having any HDP or GDM compared with not having HDP or GDM, respectively (reference). The outcome was offspring CVH at ages 10 to 14 years, based on four metrics: body mass index, blood pressure, total cholesterol level, and glucose level. Each metric was categorized as ideal, intermediate, or poor using a framework provided by the American Heart Association. The outcome was primarily defined as having at least one CVH metric that was non-ideal versus all ideal (reference), and secondarily as the number of non-ideal CVH metrics: at least one intermediate metric, one poor metric, or at least two poor metrics versus all ideal (reference). Modified Poisson regression with robust error variance was used and adjusted for covariates at pregnancy enrollment, including field center, parity, age, gestational age, alcohol or tobacco use, child's assigned sex at birth, and child's age at follow-up.

RESULTS: Among 3,317 maternal-child dyads, the median (IQR) ages were 30.4 (25.6, 33.9) years for pregnant individuals and 11.6 (10.9, 12.3) years for children. During pregnancy, 10.4% of individuals developed HDP and 14.6% developed GDM. At follow-up, 55.5% of offspring had at least one non-ideal CVH metric. In adjusted models, having HDP (aRR 1.14; 95% CI 1.04, 1.25) or having GDM (aRR 1.10; 95% CI 1.02, 1.19) was associated with greater risk that offspring developed less-than-ideal CVH at ages 10 to 14 years. The above associations strengthened in magnitude as the severity of adverse CVH metrics increased (i.e., with the outcome measured as >1 intermediate, 1 poor, and >2 poor adverse metrics), albeit the only statistically significant association was with the "1-poor-metric" exposure.