Perinatal outcomes among foreign-born and US-born Chinese Americans, 1995-2000

Neonatal mortality among disaggregated Asian American and Native Hawaiian/Pacific Islander populations

OBJECTIVE

We compared neonatal (<28 days) mortality rates (NMRs) across disaggregated Asian American and Native Hawaiian/Pacific Islander (AANHPI) groups using recent, national data.

STUDY DESIGN

We used 2015-2019 cohort-linked birth-infant death records from the National Vital Statistics System. Our sample included 61,703 neonatal deaths among 18,709,743 births across all racial and ethnic groups. We compared unadjusted NMRs across disaggregated AANHPI groups, then compared NMRs adjusting for maternal sociodemographic, maternal clinical, and neonatal risk factors.

RESULTS

Unadjusted NMRs differed by over 3-fold amongst disaggregated AANHPI groups. Native Hawaiian/Pacific Islander neonates in aggregate had the highest fully-adjusted odds of mortality (OR: 1.08 [95% CI: 0.89, 1.31]) compared to non-Hispanic White neonates. Filipino, Asian Indian, and Other Asian neonates experienced significant decreases in odds ratios after adjusting for neonatal risk factors.

CONCLUSION

Aggregating AANHPI neonates masks large heterogeneity and undermines opportunities to provide targeted care to higher-risk groups.

Racial variations of adverse perinatal outcomes: A population-based retrospective cohort study in Ontario, Canada

Introduction

Racial differences in adverse maternal and birth outcomes have been studied in other countries, however, there are few studies specific to the Canadian population. In this study, we sought to examine the inequities in adverse perinatal outcomes between Black and White pregnant people in Ontario, Canada.

Methods

We conducted a population-based retrospective cohort study that included all Black and White pregnant people who attended prenatal screening and had a singleton birth in any Ontario hospital (April 1^st, 2012-March 31^st, 2019). Poisson regression with robust error variance models were used to estimate the adjusted relative risks of adverse perinatal outcomes for Black people compared with White people while adjusting for covariates.

Results

Among 412,120 eligible pregnant people, 10.1% were Black people and 89.9% were White people. Black people were at an increased risk of gestational diabetes mellitus, preeclampsia, placental abruption, preterm birth (<37, <34, <32 weeks), spontaneous preterm birth, all caesarean sections, emergency caesarean section, low birth weight (<2500g, <1500g), small-for-gestational-age (<10th percentile, <3^rd percentile) neonates, 5-minute Apgar score <4 and <7, neonatal intensive care unit admission, and hyperbilirubinemia requiring treatment but had lower risks of elective caesarean section, assisted vaginal delivery, episiotomy, 3rd and 4th degree perineal tears, macrosomia, large-for-gestational-age neonates, and arterial cord pH≤7.1, as compared with White people. No difference in risks of gestational hypertension and placenta previa were observed between Black and White people.

Conclusion

There are differences in several adverse perinatal outcomes between Black and White people within the Ontario health care system. Findings might have potential clinical and health policy implications, although more studies are needed to further understand the mechanisms.

The Racial Configuration of Parent Couples and Premature Birth: an Analysis of the Utah Population Database

In this paper, we analyze detailed maternal and paternal race information in a 25-year time series of birth record data to consider racial inequities in premature births experienced by women of color and women within interracial parent couples. We analyze birth outcomes within Utah, a historically racially homogeneous state experiencing growing racial diversity and interracial marriage over the past two decades. Our analyses consider disparities in preterm birth according to maternal race and the interracial status of couples for all birth certificate records within the Utah Population Database from 1989 to 2015 (N = 1,148,818). Our results, consistent with a dyadic perspective on minority stress, indicate that maternal race and interracial parent-couple status are each significantly associated with heightened risk of premature birth. The odds of preterm birth are significantly greater among all four racialized groups in the analyses (African Americans, Asians, Native Americans, and Native Hawaiian or Pacific Islanders) as compared to White women. Furthermore, we find that mothers in mixed-race parent couples with either a white or a black father experience a greater risk of preterm birth than mothers parenting with a father of the same race. Our results suggest that in order to capture the complete perspective on racial-ethnic disparities in adverse birth outcomes, outcomes pivotal for subsequent health outcomes over the life course, it is critical to address racism's toxic effects across multiple levels of lived experience-from the individual level, to the parent dyad, to the local community and beyond.

Risk of Stillbirth Among Foreign-Born Mothers in the United States

The objective of this study is to assess the impact of maternal nativity on stillbirth in the US. We utilized the US Birth Data and Fetal Death Data for the years 2014-2017. Our analysis was restricted to live and stillbirths (N= of 14,867,880) that occurred within the gestational age of 20-42 weeks. The fetuses-at risk approach was used to generate stillbirth trends by gestational age. Adjusted Cox proportional hazards regression model was utilized to estimate the association between maternal nativity and stillbirth. Overall, the gestational week-specific prospective risk of stillbirth was consistently higher for native-born than their foreign-born mothers. Foreign-born mothers were 20% less likely to experience stillbirth than their native-born counterparts (AHR = 0.80; 95% CI = 0.78-0.81). Delineating the factors influencing the observed effect of maternal nativity on birth outcomes should be a research priority to inform strategies to address adverse birth outcomes in the US.

Comparison of adverse perinatal outcomes between Asians and Caucasians: a population-based retrospective cohort study in Ontario

BACKGROUND

Racial disparities in adverse perinatal outcomes have been studied in other countries, but little has been done for the Canadian population. In this study, we sought to examine the disparities in adverse perinatal outcomes between Asians and Caucasians in Ontario, Canada.

METHODS

We conducted a population-based retrospective cohort study that included all Asian and Caucasian women who attended a prenatal screening and resulted in a singleton birth in an Ontario hospital (April 1st, 2015-March 31st, 2017). Generalized estimating equation models were used to estimate the independent adjusted relative risks and adjusted risk difference of adverse perinatal outcomes for Asians compared with Caucasians.

RESULTS

Among 237,293 eligible women, 31% were Asian and 69% were Caucasian. Asians were at an increased risk of gestational diabetes mellitus, placental previa, early preterm birth (< 32 weeks), preterm birth, emergency cesarean section, 3rd and 4th degree perineal tears, low birth weight (< 2500 g, < 1500 g), small-for-gestational-age (<10th percentile, <3rd percentile), neonatal intensive care unit admission, and hyperbilirubinemia requiring treatment, but had lower risks of preeclampsia, macrosomia (birth weight > 4000 g), large-for-gestational-age neonates, 5-min Apgar score < 7, and arterial cord pH ≤7.1, as compared with Caucasians. No difference in risk of elective cesarean section was observed between Asians and Caucasians.

CONCLUSION

There are significant differences in several adverse perinatal outcomes between Asians and Caucasians. These differences should be taken into consideration for clinical practices due to the large Asian population in Canada.

Comparing Birth Outcomes in Hawai'i between US- and Foreign-Born Women

The objective of this study is to examine the relationship between maternal nativity status and preterm birth (PTB) or low birth weight (LBW) for Hawai'i resident mothers, to compare these relationships across different maternal race/ethnicity groups, and to identify other potential risk and protective factors related to PTB and LBW. Using the 2004 Natality Birth Data from the National Vital Statistic System of the National Center for Health Statistics, crude and adjusted odds ratios were calculated using logistic regression to determine maternal racial/ethnic-specific nativity effects on PTB and LBW. Other Asian or Pacific Islander foreign-born mothers had higher unadjusted rates of PTB, and Samoan foreign-born mothers had lower rates of LBW after adjusting for the socio-demographic covariates compared to their native-born counterparts. Given the limitation of this study particularly relating to data quality, further research is needed to identify socio-contextual factors that are involved in the relationship between nativity status and PTB/LBW.

Pregnancy and Birth Outcomes Among Immigrant Women in the US and Europe: A Systematic Review

Human migration is not a new phenomenon, but it has changed significantly with the advance of globalization. We focus on differences in the published literature concerning migration and health (EU vs the US), centering specifically on reproductive health outcomes. We conducted a literature search in the Pubmed and Embase databases. We reviewed papers that contrast migrants to native-born populations and analyzed differences between countries as well as challenges for future research. The prevalence of low birthweight among migrants varies by the host country characteristics as well as the composition of migrants to different regions. The primary driver of migrant health is the migrant "regime" in different countries at specific periods of time. Future health outcomes of immigrants will depend on the societal characteristics (legal protections, institutions and health systems) of host countries.

Maternal Birthplace is Associated with Low Birth Weight Within Racial/Ethnic Groups

Introduction While disparities in low birth weight (LBW) incidence by racial/ethnic group are well known, differences in LBW incidence by maternal birthplace within racial/ethnic groups, and particularly, differences after adjustment for pregnancy complications, are less clear. Methods We conducted a population-based study of LBW using 113,760 singleton, live birth records from King County, Washington (2008-2012), a region in the Pacific Northwest with a large immigrant population. Study participants were Asian, non-Hispanic black, Hispanic, Native Hawaiian/Other Pacific Islander (NHOPI), and non-Hispanic white women. Using multivariable logistic regression models, we calculated odds ratios (ORs) and 95% confidence intervals (CIs) to estimate relative risk of LBW (<2500 g) related to maternal race/ethnicity and birthplace (defined by the Millennium Development Goals Regional Groupings). Results Compared with non-Hispanic white women, non-Hispanic black, Asian Indian, Filipino, Japanese, and Vietnamese women had 1.57-2.23-fold higher, statistically significant, risk of having a LBW infant, and NHOPI and Mexican women had 1.30-1.33-fold, statistically significant, higher risk. LBW risk was lower for Asian women from Eastern Asia (OR 0.68, 95% CI 0.55-0.85), non-Hispanic black women from Sub-Saharan Africa (OR 0.58, 95% CI 0.47-0.73), and non-Hispanic white women from other developed countries (OR 0.83, 95% CI 0.69-1.00), as compared with their US-born racial/ethnic counterparts. Results were, in general, similar after adjustment for pregnancy complications. Conclusions Compared with most other racial/ethnic groups, non-Hispanic whites had lower risk of LBW. Foreign-born women had lower risk of LBW compared with their US-born counterparts in the majority of racial/ethnic groups. Pregnancy complications had minimal effect on the associations.

Ethnic disparities in the risk of adverse neonatal outcome after spontaneous preterm birth

OBJECTIVE

To describe ethnic disparities in the risk of spontaneous preterm birth and related adverse neonatal outcome.

DESIGN

Nationwide prospective cohort study.

SETTING

The Netherlands, 1999-2007.

POPULATION

Nine hundred and sixty-nine thousand, four hundred and ninety-one singleton pregnancies with a spontaneous onset of labor.

METHODS

We investigated ethnic disparities in perinatal outcome for European white, African, South-Asian, Mediterranean and East-Asian women. We performed multivariate logistic regression analyses to calculate the adjusted odds ratio (aOR) and confidence intervals (CIs) of spontaneous preterm birth and the risk of subsequent neonatal morbidity and mortality.

MAIN OUTCOME MEASURES

The primary outcome measure was spontaneous preterm birth before 37 completed weeks of gestation. Secondarily, we investigated subsequent adverse neonatal outcome, which was a composite outcome of intraventricular hemorrhage, bronchopulmonary dysplasia, infant respiratory distress syndrome, neonatal sepsis or neonatal mortality within 28 days after birth.

RESULTS

Compared with European whites, the aOR of delivering preterm was 1.33 (95% CI 1.26-1.41) for African women, 1.58 (95% CI 1.47-1.69) for South-Asians, 0.88 (95% CI 0.84-0.91) for Mediterraneans and 1.04 (95% CI 0.98-1.11) for East-Asians. Subsequent odds of adverse neonatal outcome were significantly lower for African (aOR 0.51; 95% CI 0.41-0.64) and Mediterranean women (aOR 0.86; 95% CI 0.75-0.99) when compared with European whites.

CONCLUSIONS

African and South-Asian women are at higher risk for preterm birth than European white women. However, the harmful effect of preterm birth on neonatal outcome is less severe for these women.

Perinatal outcomes and nativity: does place of birth really influence infant health?

In recent years nativity or nation of origin has become the focus of numerous pregnancy outcome studies. A recent research synthesis found that, although considerable heterogeneity in study designs hinders the development of broad generalizations concerning differences in pregnancy outcomes, migrant women were more likely to have better low-birthweight and preterm birth outcomes than women born in the receiving country in most of the studies that could be incorporated in the meta-analysis. Researchers considering studies of migration and pregnancy outcomes should incorporate more comprehensive measures of the migrant experience, as the dichotomous variable born or not born in the receiving country only opens the door to understanding the meaning of empirical observations concerning advantage or disadvantage in outcomes of pregnancy among migrant women.

Maternal morbidity and perinatal outcomes among foreign-born Cambodian, Laotian, and Vietnamese Americans in Washington State, 1993-2006

This study examined differences in perinatal outcomes of Southeast Asian (SEA) women compared with non-Hispanic white women in Washington. Using linked birth certificate and hospitalization discharge records for the years 1993-2006, we compared singleton births of Cambodian (3,858), Laotian (2,223), and Vietnamese (12,949) women with a random sample of white women (35,581). Associations between maternal nativity and perinatal outcomes were assessed using multivariable logistic regression. There are clear nativity differences among SEAs for gestational diabetes mellitus, anemia, placenta previa and febrile illness. SEAs had increased risks for these disorders when compared with white women. Compared with infants delivered of white women, infants of SEAs had increased risks for moderate to heavy meconium, birth injury and low birth weight. Differences in nativity among SEAs (populations that are traditionally studied in aggregate) should be considered when designing and carrying out interventions to prevent adverse pregnancy morbidity and outcomes among immigrants.

Interethnic mating and risk for preterm birth among Arab-American mothers: evidence from the Arab-American Birth Outcomes Study

Arab ethnicity (AE) mothers have lower preterm birth (PTB) risk than white mothers. Little is known about the determinants of PTB among AE women or the role of interethnic mating in shaping PTB risk among this group. We assessed the relationship between interethnic mating and risk for PTB, very PTB, and late PTB among AE mothers. Data was collected for all births (N = 21,621) to AE women in Michigan between 2000 and 2005. Self-reported ancestry was used to determine paternal AE as well as to identify AE mothers. We used bivariate chi-square tests and multivariable logistic regression to assess the relationship between paternal non-AE and risk for PTB, very PTB, and late PTB among AE mothers. All analyses were also conducted among non-Arab white mothers as a control. Among AE mothers, paternal non-Arab ethnicity was associated with higher risk of PTB (OR = 1.18, 95% CI = 1.06, 1.30) and late PTB (OR = 1.24, 95% CI = 1.20, 1.38) compared to paternal Arab ethnicity. Paternal non-Arab ethnicity was not associated with risk for any outcome among non-Arab white mothers. Future studies could assess the causal mechanisms underlying the association between interethnic mating and risk for PTB.

Do foreign- and U.S.-born mothers across racial/ethnic groups have a similar risk profile for selected sociodemographic and periconceptional factors?

BACKGROUND

We examined differences in selected pregnancy-related risk factors, including maternal sociodemographic characteristics, health-related conditions, and periconceptional behavioral factors, among foreign-born versus U.S.-born control mothers across race/ethnic groups.

METHODS

We used data from the National Birth Defects Prevention Study, and calculated odds ratios (ORs) and 95% confidence intervals (CIs) of the risk factors, for foreign-born Hispanic, non-Hispanic white, non-Hispanic black, and Asian/Pacific Islander (API) mothers, compared to their U.S.-born counterparts.

RESULTS

Across all race/ethnic groups, foreign-born mothers were older and had lower odds of obesity compared to their U.S.-born counterparts. With the exception of foreign-born black mothers, foreign-born mothers from other race/ethnic groups had significantly lower odds of binge drinking during the periconceptional period. Compared to U.S.-born, foreign-born Hispanic mothers had twice the odds of gestational diabetes (OR = 2.23; 95% CI = 1.36-3.66). Certain health behaviors were less prevalent in foreign-born black mothers (e.g., folic acid use; OR = 0.54; 95% CI = 0.31-0.96) and foreign-born API mothers (e.g., cigarette smoking; OR = 0.10; 95% CI = 0.02-0.48).

CONCLUSIONS

Significant differences in pregnancy related risk factors during the periconceptional period and throughout pregnancy were observed between maternal nativity groups and across race/ethnicity. Prevention efforts for both prepregnancy and after conception should be designed and delivered according to maternal nativity for each racial/ethnic group.

Perinatal outcomes in native Chinese and Chinese-American women

This study aimed to compare perinatal outcomes in native Chinese, foreign-born and US-born Chinese-American women by analysing a cohort of 950,624 singleton pregnancies in south-east China and 293,849 singleton births from the US live and stillbirth certificates from 1995 to 2004. Only births at 28 weeks or later were included. Compared with US-born Chinese-American women, native Chinese and foreign-born Chinese-American women had substantially lower risks of having a small-for-gestational age (SGA) infant (adjusted relative risk [aRR] ranging from 0.46 to 0.66) or preterm birth (aRR ranging from 0.53 to 0.82). While having a White or Black father had a reduced risk of SGA (aRR=0.45 and 0.62, respectively), it has an increased risk for preterm birth (aRR=1.13 and 1.57, respectively). Infants with Chinese father and foreign-born mother were heavier than those with Chinese father and US-born mothers. All findings were statistically significant. Our findings demonstrated the protective role of foreign-born status on low birthweight and preterm delivery. The paternal contribution to fetal size is substantial.

The differential association between education and infant mortality by nativity status of Chinese American mothers: a life-course perspective

OBJECTIVES

Integrating evidence from demography and epidemiology, we investigated whether the association between maternal achieved status (education) and infant mortality differed by maternal place of origin (nativity) over the life course of Chinese Americans.

METHODS

We conducted a population-based cohort study of singleton live births to US-resident Chinese American mothers using National Center for Health Statistics 1995 to 2000 linked live birth and infant death cohort files. We categorized mothers by nativity (US born [n = 15 040] or foreign born [n = 150 620]) and education (≥ 16 years, 13-15 years, or ≤ 12 years), forming 6 life-course trajectories. We performed Cox proportional hazards regressions of infant mortality.

RESULTS

We found significant nativity-by-education interaction via stratified analyses and testing interaction terms (P < .03) and substantial differentials in infant mortality across divergent maternal life-course trajectories. Low education was more detrimental for the US born, with the highest risk among US-born mothers with 12 years or less of education (adjusted hazard ratio = 2.39; 95% confidence interval = 1.33, 4.27).

CONCLUSIONS

Maternal nativity and education synergistically affect infant mortality among Chinese Americans, suggesting the importance of searching for potential mechanisms over the maternal life course and targeting identified high-risk groups and potential downward mobility.

Birth outcomes of Koreans by birthplace of infants and their mothers, the United States versus Korea, 1995-2004

The acculturation effect of immigrant women on birth outcomes varies by race. We examined birth outcomes of three groups of births for the period 1995-2004, USA births to the USA-born Korean mothers, USA births to the non-USA-born Korean mothers, and births in Korea. In singleton USA births to both Korean parents, average birth weight was 3,294 g for the USA-born Korean mothers and 3,323 g for the non-USA-born Korean mothers. However, this difference was not significant, once controlled for other maternal sociodemographic, obstetric and medical factors. Low birth weight and prematurity prevalence were not different by maternal nativity between these two singleton groups. Average birth weight of all births including multiplets in Korea was 3,270 g, compared to 3,297 g for all USA-born infants including multiplets and births either to both or one Korean parents. This difference might have reflected a significantly lower educational attainment of mothers in Korea compared to Korean mothers in the USA. Low birth weight rate was consistently lower in infants born in Korea compared to the USA-born, but this difference became less, 4.2% and 4.6% respectively by 2004. These observations suggest that in the USA acculturation effect of Korean immigrants on birth outcomes is negligible.

Perinatal outcomes for Asian, Native Hawaiian, and other Pacific Islander mothers of single and multiple race/ethnicity: California and Hawaii, 2003-2005

OBJECTIVES

We examined characteristics and birth outcomes of Asian/Pacific Islander (API) mothers to determine whether differences in outcomes existed between mothers of single race/ethnicity and multiple race/ethnicity.

METHODS

We used data from California and Hawaii birth certificates from 2003 through 2005 to describe variation in birth outcomes for API subgroups by self-reported maternal race/ethnicity (single versus multiple race or API subgroup), and we also compared these outcomes to those of non-Hispanic White women.

RESULTS

Low birthweight (LBW) and preterm birth (PTB) varied more among API subgroups than between mothers of single versus multiple race/ethnicity. After adjustment for sociodemographic and behavioral risk factors, API mothers of multiple race/ethnicity had outcomes similar to mothers of single race/ethnicity, with exceptions for multiple-race/ethnicity Chinese (higher PTB), Filipino (lower LBW and PTB), and Thai (higher LBW) subgroups. Compared with single-race non-Hispanic Whites, adverse outcomes were elevated for most API subgroups: only single-race/ethnicity Korean mothers had lower rates of both LBW (3.4%) and PTB (5.6%); single-race/ethnicity Cambodian, Laotian, and Marshallese mothers had the highest rates of both LBW (8.8%, 9.2%, and 8.4%, respectively) and PTB (14.0%, 13.7%, and 18.8%, respectively).

CONCLUSIONS

Strategies to improve birth outcomes for API mothers should consider variations in risk by API subgroup and multiple race/ethnicity.