The purpose of this position paper is to guide further debate and decision-making by the American Public Health Association regarding public policy statements and practices to address the critical issue of racial/ethnic and socioeconomic disparities in preterm birth and low birthweight. This position paper provides the scientific basis and justification for the importance of addressing the issue of racial/ethnic and socioeconomic disparities in these birth outcomes, and outlines a broad course of action to reduce the excess risk of preterm and low birthweight births in minority and low-income populations. In particular, this paper emphasizes the importance of creating interventions at both the individual and societal or macro level (communities, health care systems, and government agencies) to address the problem of birth outcome disparities. This position paper will enable APHA to become a policy leader in addressing racial/ethnic and socio-economic differentials in preterm birth and low birthweight. The objectives of this position paper are for APHA to be well positioned to:
II. The Problem- Scientific Basis
A) Overview of the Problem of Preterm Delivery and Low Birthweight
Preterm delivery and low birthweight are serious birth outcomes that can have negative consequences, not only for infants and their families, but for our communities and our nation as a whole. Preterm delivery, defined as a delivery before 37 weeks of gestation, is "currently the most important problem in maternal-child health in the United States."1,2 The rate of preterm births has increased 27 percent over the past 20 years from fewer than one in ten live births (9.4 percent) in 1981, to one in eight (12.4 percent) in 2004.3,4, 5 This rise in the preterm birth rate has been fairly steady, except for small declines in 1984 (from 9.6 to 9.4) and 1992 (from 10.8 to 10.7) (Martin et al, 2005) and with no change in the rate from 1993 to 1997 (at 11.0). Low birthweight (less than 2500 grams or 5 lbs., 8 oz.) is highly correlated with preterm birth. The international ranking of the United States for low weight births has worsened from 20th in 1980 to 40th in 2000 among countries reporting to the United Nations.6 The rate of low birthweight births has increased 16percent over the past two decades from 6.8 in 1981 to 8.1 in 2004 .4,5, Martin et al., 2005 There was a slight increase in the low birthweight rate in the 1980s (from 6.8 in 1981 to 7.0 in 1989), with larger changes occurring in the 1990s (from 7.0 in 1990 to 7.6 in 1999) and during the new millennium (from 7.6 in 2000 to 8.1 in 2004). 4
Babies who are born preterm and/or at low birthweight are at increased risk for death in the first year of life. 3,7 The loss of a baby can be a devastating experience for a family. Infant mortality (i.e. death of an infant less than one year of age) is an even greater tragedy when the death was due to a preventable preterm and/or low birthweight birth. Babies born very early or at a very low birthweight are at greater risk of dying before their first birthday. Nearly half of those infants born at less than 28 weeks of gestation or at less than 1,000 grams will not survive their first year of life.8
Many preterm and low birthweight infants that survive the perinatal period are rendered highly vulnerable to a host of childhood morbidities spanning a variety of functional domains, such as cerebral palsy, chronic lung disease, and attention deficit/hyperactivity disorder.9
Adolescents born prior to 35 weeks of completed gestation have been shown to have a higher degree of abnormal brain development and cognitive and behavioral problems than adolescents born full-term.10 These poorer birth outcomes have also been associated with serious health conditions in adulthood, such as cardiovascular disease, Type II diabetes, and hypertension.11,12,13 More than just a concern for a single individual in a particular generational cohort, a mother's own birth outcomes have been linked to those of her infant, suggesting that low birthweight and preterm delivery can be perpetuated across generations. 14,15,16
Additionally, the financial costs associated with treating preterm labor and delivery are quite high. According to the Nationwide Inpatient Sample for 2003, a database sponsored by the Agency for Healthcare Research and Quality of nearly 8 million all-payer inpatient hospital stays from a sample of 994 U.S. community hospitals, hospital charges for inpatient stays with any diagnoses of prematurity/low birthweight averaged $44,000, in comparison to hospital charges averaging $1,700 for newborn stays without complications. 17,18 Total hospital charges for preterm infants in the United States were estimated to be $18.1 billion in 2003. 17 Between 2002 and 2003, hospital charges for infants with a diagnosis of prematurity/low birthweight increased 16 percent.17
B) Persistent Racial/Ethnic and Socioeconomic Disparities
Significant and persistent disparities in preterm birth and low birthweight exist: some minority populations (in particular, African Americans and Native Americans) and poor women are at far greater risk for these poor birth outcomes.19, 20 In order to achieve the Healthy People 2010 objectives of eliminating health disparities and reducing the rate of preterm births to 7.6 percent and low birthweight to 5 percent, much work needs to be done to further characterize the causal pathways that lead to higher rates of preterm delivery and low birthweight births in minority and poor women. 21
A comparison of African American and Native American to non-Hispanic white births depicts a troubling difference in the rates of preterm birth. The percentage of non-Hispanic African American infants that were preterm in 2004 was 17.9 percent, versus 11.5 percent of non-Hispanic white infants.5 Trend data indicate that the African American rate of preterm delivery is consistently 1.5 to 2.4 times higher than that of their non-Hispanic white counterparts.22 The preterm birth rate of American Indian/Alaska Native women, 13.7 percent in 2004, is also higher than the national average and is second only to the African American rate.5 Other vulnerable groups include Puerto Rican women, whose preterm delivery rate was 13.8 in 2003. 4
Low birthweight, which is correlated with preterm birth, follows a somewhat different pattern of disparities. Non-Hispanic blacks or African Americans remain at highest risk: the percentage of low birthweight births for non-Hispanic blacks or African Americans nearly doubles that of non-Hispanic whites (13.6 vs.7.0 percent, 2003). 23 Other populations at risk for low birthweight in comparison to non-Hispanic whites include Puerto Ricans (9.7 percent), Filipinos (8.6 percent), Hawaiians (8.1 percent), Japanese (7.6 percent), American Indians or Alaska Natives (7.2 percent) (2002 data). 23
Infants of women with low socioeconomic status of any race or ethnic group are more likely to be preterm, low birthweight, and to die before one month of age.24, 25 Although race and class are closely aligned in this country, socioeconomic differentials do not fully explain racial differentials in poor birth outcomes, as higher rates of preterm birth and low birthweight are still evident in African Americans even after socioeconomic factors have been controlled.26-28 Further, increases in assisted reproductive technology (ART), which has contributed to increasing numbers of preterm and low birthweight births, also are unlikely to account for the disparities between African American and non-Hispanic white birth outcomes, given that only 0.1 percent of African American women have undergone ART as compared to 0.4 percent of non-Hispanic white women). 29
Clearly, socioeconomic determinants cannot "explain away" racial and ethnic disparities in poor birth outcomes. Other individual determinants of poor birth outcomes must be considered, including factors that might provide a protective effect against low birthweight and preterm births. For example, some immigrant groups have been found to be less likely to have a low birthweight infant in comparison to their U.S. born counterparts, controlling for socio-economic factors. 31,32 Though the effect is not consistent across all immigrant groups, the "healthy immigrant" effect appears consistent within the overall immigrant Latina population. 31-33 The "healthy immigrant effect" deserves further study. 31
While individual-level determinants of preterm delivery and low birthweight, such as poor diet, chronic health issues such as diabetes and hypertension, substance use, and extremes of age and weight, can help to explain disparities, approximately half of preterm births have no identifiable risk factor.30, 34 Identifying the causes of racial/ethnic and socioeconomic status disparities in birth outcomes has proven quite challenging.35 For example, well-established medical, behavioral, and sociodemographic risk factors have been unable to fully account for persistent racial disparities, prompting a re-examination of conventional explanatory models. 36,37
Among many researchers, attention has been shifting from individual-level causes of poor birth outcomes, such as negative health behaviors, to the cause of those causes- the social, political, economic, and cultural forces at the macro level that shape disease risk in populations and provide the context within which individuals function.38-41 Psychological stress, racism, and neighborhood environments are just some of the contextual factors that researchers have been investigating.42-45 Thus, both micro level and macro level factors need to be addressed.
III. A Call for Change
It is clear that disparities exist; women of racial and ethnic minority populations (especially African American and Native American women), as well as women of lower socioeconomic status, are at higher risk of delivering premature and low birthweight infants who may experience a range of health and developmental challenges. Appropriate interventions are needed to address these disparities. Educating the public and health care providers, broadening access to quality health care services, promoting healthier physical and social environments, supporting innovative research, and advocating for efforts to address racial and social inequalities can be effective tools in reducing disparities in preterm births and low birthweight.
Health care providers and the general public must be educated about the significance of preterm delivery and low birthweight as public health issues. The importance of social and economic inequities in life circumstances as underlying determinants of disparities in these adverse birth outcomes also must be acknowledged. Health care professionals must consciously adapt a culturally appropriate framework for working with different patient populations.
The Centers for Disease Control and Prevention is currently promoting preconception and interconception care (i.e., care between pregnancies where the earlier pregnancy had an adverse outcome)79 as critical to improving the health of the nation. Preconception care and care between pregnancies, which address health risks prior to and between pregnancies, and in early pregnancy, includes both prevention and health management.46 It is especially important for women who are at high risk for preterm and low birthweight births to have equitable access to both preconception or interconception care as well as care during the entire period of pregnancy (prenatal care); this care must address their unique needs in a competent manner. 35, 46-49 A REACH 2010 project in Genesee County, Michigan employs the use of maternal and infant health advocates to support African American women during pregnancy and up to the infant's first birthday to address racial disparities in infant mortality, including accompanying the woman to the doctor's appointment and providing transportation if necessary.50 Support services for behavioral change can lower preconception risks including effective interventions to curtail the use of tobacco, alcohol and illicit drugs and prevent sexually transmitted diseases.35,47,51 Women who are underweight and overweight need ways of improving their nutritional status prior to pregnancy, including knowledge of and access to nutritious and affordable food. Women who are under stress or being abused (physically, sexually or emotionally) need access to the psychosocial and community resources necessary to improve their situation.
Promoting healthier physical and social environments is also vital to our efforts to reduce disparities in low birthweight and preterm delivery. Impoverished communities and communities of color, which often are one and the same, are disproportionately exposed to environmental hazards such as lead, air pollutants, agrochemicals, and hazardous waste sites.52-54 Such exposures have been linked to reduced fertility, pregnancy loss, compromised fetal development, and preterm birth.55 Environmental cleanup and protection efforts and policies that advance environmental justice must be sensitive to the needs of affected communities and meaningfully involve them in those change efforts.56,57
Besides environmental contaminants, the social characteristics of a community also hold important implications for pregnancy outcomes. Neighborhoods that are crime-ridden, physically decayed, disorganized, socially unsupportive, and negatively perceived by the residents have been shown to negatively influence infant birthweight.58-61 These neighborhoods, often racially segregated and characterized by high levels of socioeconomic disadvantage, are likely to provide limited access to high quality medical and municipal services, grocery stores and recreational facilities, and are frequent targets of negative health messages from tobacco and alcohol companies.62-65 The physical and social environments within which individuals function need to be safe, clean, affordable, socially supportive, and adequately resourced in order to maximize every woman's potential to deliver a full-term and healthy infant.
Additional research is needed to further identify the interactive effects of environmental, social, psychological, and physiological risk factors that contribute to racial/ethnic and socioeconomic disparities in preterm and low birthweight births. These risk factors may negatively impact health and increase risk for poor birth outcomes long before a woman ever becomes pregnant. For example, studies conducted in Great Britain half a century ago 67-69 demonstrate that the socioeconomic context of a woman's childhood is significantly associated with her pregnancy outcomes in adulthood. More contemporary work suggests that childhood socioeconomic factors are important contributors to adult health outcomes more generally. 70-72 Therefore, the research agenda should include a life course approach to studying the problem of low birthweight and preterm delivery. 40,73
A stress paradigm is particularly promising for guiding work in this regard. Stressors, environmental demands that strain or overwhelm one's ability to adapt, trigger psychological and biological processes that may contribute to disease risk.66 Over time, cumulative exposure to stressors, and the psychological and physiological changes they produce, cause wear and tear on the body. This increasing inefficiency of the body's response to stressors, also known as allostatic load, can compromise functioning in key biological systems.74 Allostatic load is hypothesized to be one way in which the life challenges that social inequality produces may contribute to racial/ethnic and socioeconomic differentials in adverse birth outcomes.75 There are innovative research efforts that examine the multiple factors which contribute to low birthweight and gestational age-related outcomes.43,44,60,76 The research into allostatic load and the biological processes by which cumulative stress may result in a poor birth outcome, however, is still in the early stages.75 Innovative research efforts to develop and test multidimensional, multi-level models of low birthweight and preterm delivery must be supported and encouraged.
Finally, the American Public Health Association and other health care organizations should advocate that future efforts to reduce preterm birth and low birthweight include a focus on the broad, multifactorial causes of disparities in these newborn outcomes; this would include examining the social, political, economic, and cultural forces at the macro level that shape disease risk in populations and provide the context within which individuals function. The March of Dimes launched its five-year, $75 million Prematurity Campaign in 2003 to increase public understanding of the seriousness of prematurity and its reducible risk factors, to assist health care providers to improve the prevention and management of preterm labor, and to expand federal research funding by $50 million to prevent and stop preterm labor. However, education, research, intervention and advocacy efforts aimed at reducing social and racial inequities need to be a national priority if disparities in prematurity and low birthweight rates are to decline.77.78
IV. Goals for APHA
Eliminating racial/ethnic and socioeconomic disparities in health is a priority of the American Public Health Association and one of the two major goals of Healthy People 2010, the nation's public agenda. Therefore, to reduce racial/ethnic and socioeconomic disparities in preterm delivery and low birthweight, the American Public Health Association will work with its members, health care providers, advocates, policy-makers, government agencies, health insurance providers, other appropriate organizations, and/or communities to:
References
