Preterm birth among Pacific Islanders in the United States and the US‐affiliated Pacific Islands: A systematic review and meta‐analysis

Abstract

Objective To better understand the epidemiology of preterm birth among Pacific Islanders in the United States and the US‐Affiliated Pacific Islands. Methods Systematic searches of MEDLINE, Embase, CINAHL, PsycINFO, two nonindexed regional journals, and gray literature were conducted and finalized in September 2021. Observational studies published since January 2010 that documented preterm birth outcomes among Pacific Islanders in the United States and the US‐Affiliated Pacific Islands were eligible for inclusion. Outcomes of interest included preterm birth prevalence, risk compared with white women, and risk factors for preterm birth among Pacific Islanders. Results Fourteen of the 3183 screened articles were included in meta‐analyses. Random‐effects models were used for pooled estimates with 95% confidence intervals. The pooled prevalence of preterm birth among Pacific Islanders was 11.2%, 95% CI: 9.3%‐13.6%. Marshallese women had the highest pooled prevalence (20.7%, 95% CI 18.6%‐23.0%) among Pacific Islander subgroups. Compared with white women, Pacific Islander women had higher odds of experiencing preterm birth (OR = 1.40, 95% CI: 1.28‐1.53). Four risk factors for preterm birth could be explored with the data available: hypertension, diabetes, smoking, and pre‐pregnancy body mass index; hypertension and diabetes significantly increased the odds of preterm birth. Conclusions Existing literature suggests that United States Pacific Islanders were more likely to experience preterm birth than white women, although the pooled prevalence varied by Pacific Islander subgroup. Data support the need for disaggregation of Pacific Islanders in future research and argue for examination of subgroup‐specific outcomes to address perinatal health disparities.

Preterm Birth Risk and Maternal Nativity, Ethnicity, and Race

“…Thus, to ensure that undercounted people receive better benefit from research and associated health care interventions, innovative ways to reclassify individuals who select the other racial and ethnic category should be explored, such as offering more detailed self-identification options on surveys or applying machine-learning techniques to evaluate write-in responses to the other category. Native Hawaiian or Other Pacific Islander populations are another group underrepresented in perinatal research and are often aggregated with Asian people, which may mask their unique outcomes given the heterogeneity within both Native Hawaiian or Other Pacific Islander and Asian subgroups . Native Hawaiian or Other Pacific Islander birth outcomes are important to study as they are one of the fastest-growing minoritized groups in the US, with substantial intragroup variation in perinatal outcomes …”

“…Native Hawaiian or Other Pacific Islander populations are another group underrepresented in perinatal research 38 and are often aggregated with Asian people, which may mask their unique outcomes given the heterogeneity within both Native Hawaiian or Other Pacific Islander and Asian subgroups. 39,40 Native Hawaiian or Other Pacific Islander birth outcomes are important to study as they are one of the fastest-growing minoritized groups in the US, 41 with substantial intragroup variation in perinatal outcomes. 17 Second, we found that non-US-born Native Hawaiian or Other Pacific Islander birthing people did not experience the immigrant paradox or the expected non-US-born advantage in preterm birth.…”

Pre‐pregnancy BMI, rate of gestational weight gain, and preterm birth among US Pacific Islander individuals

“…We then used Cox proportional hazard regression models to examine associations between characteristics and PTB, with the time variable of GA at birth. Covariates in the univariable models were selected based on previous literature [3,8,23],…”

“…Among US singletons born without congenital anomalies, PTB prevalence increased from 7.6% to 8.1% [2] between 2014 and 2018, with Black women having the highest (11.2%) and White women having the lowest prevalence (7.2%) [2]. Pacific Islander women in the United States (PTB prevalence: 11.2%) [3] also have a higher risk of PTB compared with White women [3], but our understanding of risk factors underlying this disparity is limited because Pacific Islander individuals have been traditionally aggregated with Asian American individuals, whose demographic characteristics and biomedical risk profiles are quite dissimilar [4].…”

“…Pacific Islander adults were approximately three times as likely to have obesity than Asian American adults (2014) and were 80% more likely compared with White American adults (2016) [6]. In a single prior study, however, no association between obesity and PTB was observed among Pacific Islander women [3]. Beyond pre-pregnancy body mass index (BMI), gestational weight gain (GWG) is another important indicator for PTB and consistently modifies the association of pre-pregnancy BMI with PTB (and vice versa) [8,9].…”