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To examine the extent to which racial disparities exist in the perinatal outcomes of beneficiaries of the Military Health System (MHS).
We searched the PubMed, CINAHL, and Embase databases.
We selected articles published in English in peer-reviewed journals in which the authors examined race in relation to perinatal outcomes among beneficiaries of the MHS. Date of publication was unrestricted through March 2021.
Twenty-six articles met the inclusion criteria. We extracted data about study design, purpose, sample, setting, and results. We also assigned quality appraisal ratings to each article.
In most of the included articles, researchers observed differences in perinatal outcomes between Black and White women. Compared to White women, Black women had greater rates of cesarean birth, preterm birth, low birth weight, and small for gestational age neonates. White women had greater rates of postpartum depression than Black women.
Racial disparities in very low birth weight newborns and preterm birth may be smaller in the MHS than in the general population of the United States. The overall rates of preterm birth, cesarean birth, and neonatal mortality were lower for beneficiaries of the MHS than in the general population of the United States.
). The Healthy People 2020 Social Determinants of Health framework includes five key determinants of health: economic stability, education, social and community context, health and health care, and the neighborhood and built environment (
). Research conducted in the general U.S. population has shown that low socioeconomic status, employment status, poor access to health care, level of education, and insecure housing are associated with disparities in perinatal outcomes (
During health care for pregnancy and childbirth, women of color are more likely to receive differential treatment, and Black women are especially vulnerable. For example, women of color reported being less likely to be heard and have their concerns taken seriously (
It is currently unclear to what extent racial disparities exist in perinatal outcomes among beneficiaries of the Military Health System.
There exists an assumption that three key social determinants of health are fulfilled through association with the U.S. military: stable income, stable housing, and universal access to health care. Although there may be inherent benefits of military service in these areas, differences in income, housing, and access depend on military rank and geographic location. Although access itself could be seen as universal, health care services can vary based on availability (
). For example, perinatal specialty care is not available at all military treatment facilities (MTFs). As a result, beneficiaries of the Military Health System (MHS) receive care in the civilian health care system. Furthermore, active-duty women may not have access to perinatal care during periods of deployment or training.
A health disparity is defined as “a health difference that adversely affects disadvantaged populations” based on one or more health outcomes (
). Determining to what extent racial disparities in perinatal outcomes exist among MHS beneficiaries is a crucial step to ensure that existing health care practices and policies are optimized to support active-duty service members and their families. Supporting childbearing servicewomen is imperative because the proportion of active-duty women in the military is at an all-time high (
methodology for integrative reviews. This methodology includes problem identification, literature search, data evaluation, data analysis, and presentation of findings. We conducted a literature search to identify articles in which the authors examined race in relation to perinatal outcomes among MHS beneficiaries. We searched PubMed, CINAHL, and Embase using search strategies developed by the first author (S.E.I.) and a university health science librarian (see Supplementary Table S1). Publication date was unrestricted through March of 2021. We did not restrict articles by publication date because we also wanted to examine whether greater attention was given to racial disparities in perinatal outcomes in more recent literature.
Article selection was informed by the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and is outlined in the flowchart in Figure 1. We included articles that met the following eligibility criteria: study participants were beneficiaries of the MHS and articles were published in English language peer-reviewed journals, were reports of original research, and included examination of perinatal outcomes by race. We excluded articles about topics outside of perinatal health, such as ectopic pregnancy, and articles about health behaviors and decision making, such as abortion and breastfeeding.
Data Extraction and Quality Appraisal
We used Distiller SR from Evidence Partners to conduct the following two-step screening process: title and abstract screening and full-text screening. The first author (S.E.I.) screened all articles at each step, and the second author (A.K.P.) screened 10% of the articles independently for quality assurance. Our data extraction process included recording the author(s), year of publication, study purpose, sample, setting, and results. The first (S.E.I.) and second author (A.K.P.) divided the articles evenly and extracted data independently. Each author (S.E.I. and A.K.P.) reviewed data extraction for 25% of the articles assigned to the other person to confirm interrater reliability. We appraised the quality of the literature using the Johns Hopkins Nursing Evidence-Based Practice Model and Guidelines (
). The second author (A.K.P.) used the quality appraisal tool to assign a level of evidence and quality rating to each study. The first author (S.E.I.) reviewed and confirmed these results.
After we removed duplicates, we screened the titles and abstracts of 411 articles. Of these, we screened 60 full-text articles for inclusion. We retained 26 articles for data abstraction (see Supplementary Table S2). The authors of 12 articles stated an a priori purpose of examining differences in perinatal outcomes by racial groups. We included the remaining 14 articles in this review because the authors examined race as an independent variable in relation to perinatal outcomes.
About half (n = 12) of the articles were published more than 20 years ago, from 1983 to 2000 (
). Most studies had cohort designs using existing data such as medical records, institutional birth logs, hospital discharge records, birth certificates, and databases specific to the MHS (e.g., Department of Defense Birth and Infant Health Registry, Defense Manpower Data Center, Defense Medical Information System, and the MHS Analysis and Reporting Tool (MHS MART), most commonly called M2.
The samples of 10 studies included only active-duty women (
Maternal outcomes included antenatal hospitalization, cesarean birth, hypertensive disorders of pregnancy, placental abruption, postpartum depression, preterm birth, and severe maternal morbidity (see Figure 2). Neonatal outcomes included low birth weight, small for gestational age, and neonatal mortality. All studies had Level 3 evidence and were nonexperimental studies, except for one quasi-experimental study (
also observed a 30% increase in preterm birth associated with being a Black active-duty parent; however, a limitation of their study was that data about race were available only for the active-duty parent, which was usually the father. Preterm birth was significantly associated with interpregnancy intervals (defined as the length of time from birth to next conception) of less than 9 months for Black women compared with less than 3 months for White women (
compared MHS preterm birth rates to national rates from 2008 to 2012 and found that preterm birth rates within the MHS were significantly lower than national rates. The difference was greatest among preterm births from 33 to 36 weeks gestation, where the MHS rate was 5.9%, and the national rate was 9.6%.
found that preterm birth rates at less than 37 and 33 weeks gestation were lower for Black women in the MHS compared to national rates for Black women. However, White women in the MHS had greater rates of preterm birth than national rates for White women at 37 and 33 weeks gestation (
), which provides coverage of health care services for active-duty servicemembers, retirees, and dependent family through the MHS or the civilian health care system in cases when MTFs are not available (
Maternal age, hospital type, and insurance were all associated with racial disparities in cesarean birth rates. Black women older than 30 years were more likely to have cesarean births than White women older than 30 years (
found that from 1996 to 2002, there was a lower cesarean birth rate in the MHS compared to the national rate; however, racial disparities in cesarean birth were observed within the MHS, with the greatest rates among Black women followed by Asian women.
Low Birth Weight/Small for Gestational Age
In 10 of the included studies, researchers identified racial disparities related to neonatal size at birth (
observed that among newborns born at MTFs, Black newborns had lower birth weights than Hispanic and White newborns at every gestational age from 37 to 42 weeks.
Evidence from the Military Health System suggests smaller racial disparities in very low birth weight newborns and preterm birth as well as lower rates of preterm birth, cesarean birth, and neonatal mortality than in the general population.
In two studies, researchers found no differences in neonatal size at birth among racial groups.
compared the risk of low birth weight among infants born at MTFs to those born at civilian hospitals. These researchers found that although disparities existed in military and nonmilitary hospitals, Black women who gave birth at civilian hospitals had a greater risk of low birth weight and moderately low birth weight infants compared to Black women who gave birth at MTFs.
The authors of three studies examined maternal race in relation to neonatal mortality and found no difference among racial groups for this outcome (
observed no statistically significant difference in neonatal mortality between Black and White newborns. However, Black newborns who were born at MTFs had a significantly lower mortality rate than the national civilian neonatal mortality rate for Black newborns.
observed that White women had more cases of postpartum depression than expected, whereas Black women had fewer cases than expected.
Racial disparities in perinatal outcomes affect the short- and long-term health of women of color and their families. Although examining perinatal outcomes in the MHS offers the opportunity to explore whether addressing three key social determinants of health (i.e., stable income, stable housing, and access to health care) reduces racial disparities in perinatal outcomes, our results are limited by the descriptive, retrospective nature of reviewing existing literature. In our review of evidence published in the last four decades, we found that most researchers observed differences in perinatal outcomes between Black and White women. With the exception of mixed findings for hypertensive disorders of pregnancy, most of the evidence we reviewed suggested worse outcomes for Black women than White women for cesarean birth, preterm birth, and low birth weight or small for gestational age neonates. Postpartum depression was the only outcome that affected White women at greater rates than Black women; however, evidence of this outcome is limited to a single published study. We identified no disparities in neonatal mortality by race.
Evidence of disparities in perinatal outcomes between Black and White women in the MHS was similar to trends identified in the general population. In the literature published from 1993 to 2018, there were greater rates of preterm birth among Black women than White women in the MHS.
identified the same trend in the general population from 1971 to 2021. In the literature published from 1996 to 2021, there were greater rates of cesarean birth among Black women compared to White women in the MHS. Data from the Centers for Disease Control and Prevention show a corresponding disparity nationally from 1996 to 2007 (
). In the literature published from 1990 to 2020, there were greater rates of low birth weight or small for gestational age neonates among Black women in the MHS. Similarly, there was a greater rate of low birth weight and very low birth weight infants in the general population from 1989 to 2015 (
). In contrast with findings from an article published in 2020 in which White women had a greater rate of postpartum depression compared with Black women, the reverse was observed in national rates, where Black women had greater rates of postpartum depression compared to White women in 2004, 2008, and 2012 (
). In the literature published from 1990 to 1996, there was no disparity in neonatal mortality between Black and White infants in the MHS. By contrast, in the national data, Black infants had greater rates of neonatal mortality compared to White infants from 1989 to 2001 (
Although researchers in only five studies compared perinatal outcomes in the MHS with outcomes of the general population, evidence suggests smaller racial disparities in very low birth weight and preterm birth as well as lower rates of preterm birth, cesarean birth, and neonatal mortality than in the general population.
found a smaller disparity in preterm birth between Black women and White women in the MHS compared to those in the general population. In three studies, researchers compared rates of perinatal outcomes in the MHS with national rates.
found that from 2008 to 2012, the rates of preterm birth in the MHS were lower than national rates. Total and primary cesarean rates were lower in the MHS compared to national rates from 1996 to 2002 (
). There were temporal gaps in the published evidence where, to our knowledge, no comparisons between the MHS and nonmilitary perinatal outcomes were published in the literature from 1996 to 2004 and from 2004 to 2018. Thus, it was not possible to compare MHS and national rates of perinatal outcomes over a contiguous time line.
The presence of three critical social determinants of health—stable income, stable housing, and access to health care—may explain the smaller disparities in perinatal outcomes by race and lower overall rates of adverse perinatal outcomes in the MHS compared to the general population. Although geospatial analyses were not included in this review, evidence suggests that social and physical environments contribute to disparities in preterm birth (
). However, while active-duty service members live in stable housing units and have stable incomes, there are differences in levels of housing and income based on rank. Furthermore, evidence suggests that cumulative exposure to residential segregation and income inequality over time is associated with worse birth outcomes (
). Although researchers in fewer than half (n = 10) of the studies included in this review focused exclusively on active-duty women, it should be noted that active-duty women are more physically fit than civilian women because achieving physical fitness standards is required for job retention and career advancement in the military. A large body of evidence suggests improved perinatal outcomes in women who are physically fit and have body mass index values within a normal range (
). Another explanation is that women with more complicated cases are referred to civilian hospitals with greater capability to provide complex care for women with high-risk pregnancies. While we did not identify evidence of a relationship between care setting (MHS or civilian) and pregnancy and birth outcomes,
noted that referring higher-risk women to the civilian health care system may lower rates of adverse outcomes in the MHS. However, these factors do not explain why most of the evidence we reviewed suggests there are racial disparities in cesarean birth, preterm birth, and low birth weight/small for gestational age newborns.
The persistence of racial disparities in perinatal outcomes in the MHS suggests the presence of additional contributing factors such as those identified in the Healthy People 2020 Social Determinants of Health framework (
). For example, active-duty women may have had similar experiences to their nonmilitary counterparts earlier in life. With the exception of women who were military dependents as children, active-duty women experience a minimum of nearly two decades of life outside of the military environment and without access to the MHS before they volunteer for military service. During this time frame from childhood through early adulthood, women who eventually join the military may have similar experiences as their nonmilitary counterparts in terms of their neighborhoods and social/community contexts.
Another explanation for racial disparities in perinatal outcomes in the MHS could be differences in the use of health care services.
found that the use of prenatal care varied by race, and prenatal care was accessed most often by White women, followed by Black women and Hispanic women. A more recent national comparison of prenatal care use among these three racial groups suggests similar findings: White women had the lowest rates of no prenatal care, followed by Hispanic women, then Black women (
found that compared to White women, Asian/Pacific Islander women had a 24% increased risk and non-Hispanic Black women had a 15% risk for delayed prenatal care. Contemporary findings from a national sample showed the same results, and late use of prenatal care was greatest among Native Hawaiian or Pacific Islander women, followed by Black women, then American Indian or Alaska Native women (
Although the MHS is often perceived to be a universal health care system with equal access for all beneficiaries, there are noteworthy limitations. Variability exists across the MHS related to the availability of specialty care services. Of the more than 370 MTFs across the MHS, only 55 are full-service hospitals, and some MTFs do not have dedicated maternity care services (
). For primary care, service members are assigned to credentialed providers for their health care needs. Upon confirmation of pregnancy, active-duty women are given pregnancy profiles by their credentialed providers that include an occupational health assessment of the work area and a description of acceptable activities during the pregnancy (
). Servicewomen in deployed settings may receive care from a noncredentialed enlisted technician, such as an independent-duty corpsman or technician, for acute needs. This range of health care services is an important consideration when evaluating disparities in the MHS.
The presence of systematic racism could also explain racial disparities in perinatal outcomes. Because the military culture is a microcosm of the United States, racism persists within the military. According to a recent U.S. Department of Defense survey, nearly one third of Black servicemembers reported experiencing harassment, racial discrimination, or both during a 1-year period (
). Despite evidence of racism, the number of complaints filed by servicemembers is lower than the number among government civilian employees, which suggests the problem is more widespread than previously believed (
). Based on our review of this literature, it is unknown whether systemic racism contributes to racial disparities in perinatal outcomes among active-duty servicemembers.
Further research is needed to examine disparities in perinatal outcomes and their relationships to social determinants of health rather than race.
The findings of this integrative review are limited to studies in which researchers examined perinatal outcomes by race as identified in the title or abstract of the article. An a priori purpose to examine racial disparities in perinatal outcomes was stated in only 12 articles. To ensure the inclusion of articles with analyses of perinatal outcomes by race, we also included those in which researchers examined race as an independent variable and perinatal outcomes as a dependent variable. However, we may not have included relevant articles if this information was not presented in the title or abstract.
Our synthesis of the evidence was complicated by some noteworthy limitations. One limitation is that some researchers who conducted analyses of existing data used the active-duty parent’s race as a proxy for maternal race. This approach complicates data analysis when the active-duty parent is not the woman who experiences the perinatal outcome of interest. Additionally, attribution to a racial category may be inaccurate for mixed-race couples. We also found that few researchers compared data from the MHS to national rates, which limited our ability to compare outcomes between the MHS and the civilian health care system.
Most evidence was Level 3 (nonexperimental) and low quality. Many studies received a lower quality rating because the authors did not explicitly state the study design. This illustrates the relatively recent development of quality appraisal tools and their influence on the minimum criteria required to publish rigorous research. Although we did not observe a relationship between publication date and quality of evidence, we observed that authors of older articles were less sensitive to the complexities and implications of examining perinatal outcomes by racial group. In some cases, this resulted in study designs based on inappropriate assumptions. For example,
selected participants based on whether a woman’s first name in the birth log appeared to be of Asian heritage. Additionally, the authors of eight articles included in this review compared differences between Black and White women rather than differences among all racial groups. This approach neglects all other groups of women of color, who have unique experiences of systematic racism and health disparities in our society.
We recognize that challenges are inherent in attributing health disparities and outcomes to racial categories. The color of a woman’s skin does not determine her unique combination of social determinants of health that influence perinatal outcomes. The myopic approach of attributing health outcomes to racial categories is illustrated by national maternal mortality rates, where Black women have worse perinatal outcomes than White women regardless of level of education (
). These findings suggest that adverse perinatal outcomes may be linked to inequities in health care exacerbated by factors associated with social determinants of health and systemic racism. Although the U.S. military and the MHS are not free of systemic racism (
). The MHS is taking steps to improve the representation of people of color in leadership positions, as evidenced by the appointment of the first Black Deputy Chief Nurse and Chief Nursing Officer at Fort Belvoir Community Hospital in Virginia (
In our integrative review, evidence from the MHS suggests smaller racial disparities in very low birth weight and preterm birth as well as lower rates of preterm birth, cesarean birth, and neonatal mortality than in the general population. Research is needed to examine a more nuanced approach to measuring perinatal disparities to include social determinants of health rather than race before and during enlistment in the military. Research is also needed to examine how systemic racism contributes to racial disparities in perinatal outcomes among servicemembers.
The authors acknowledge Rhonda Allard for guiding the literature search and Jennifer Hatzfeld, whose doctoral research inspired this literature review.
Conflict of Interest
The opinions and assertions expressed herein are those of the author(s) and do not reflect the official policy or position of the Uniformed Services University of the Health Sciences, the Henry M. Jackson Foundation, Towson University, the United States Air Force, or the Department of Defense. Neither we nor our family members have a financial interest in any commercial product, service, or organization providing financial support for this research. References to non-federal entities or products do not constitute or imply a Department of Defense or Uniformed Services University of the Health Sciences endorsement. This research protocol was reviewed and approved by the Uniformed Service University of the Health Sciences institutional review board (IRB) in accordance with all applicable federal regulations. This work was prepared by military members of the US Government as part of their official duties and therefore is in the public domain and does not possess copyright protection (public domain information may be freely distributed and copied; however, as a courtesy it is requested that the Uniformed Services University and the author be given an appropriate acknowledgement).
The Military Women's Health Research Consortium supported Dr. Iobst's work on this study while she was a Senior Research Associate for the Henry M. Jackson Foundation at the Uniformed Services University.
Stacey E. Iobst, PhD, RNC-OB, C-EFM, is an assistant professor, College of Health Professions, Department of Nursing, Towson University, Towson, MD.
Angela Kornegay Phillips, PhD, APRN, WHNP-BC, is a nurse scientist, Joint Base Andrews, Suitland, MD, and an adjunct assistant professor, Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, Bethesda, MD.
Gwendolyn Foster, MSN, CNM, FAANP, FACNM, is the Commander of the 60th Medical Group, 60th Air Mobility Wing, Travis Air Force Base, CA.
Joan Wasserman, DrPh, RN, FAAN, is the Associate Dean for Research, Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, Bethesda, MD.
Candy Wilson, PhD, MHSc, MSN, APRN, WHNP-BC, FAANP, FAAN, is an associate professor, Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, Bethesda, MD.