Date of Defense:
According to national trends, the rate of low birth weight (infants weighing less than 2500 grams) continues to increase putting more children at risk of health related consequences. In 2004, the rate of low birth weight increased to 8.1 percent representing a 21 percent increase since the 1984 low (6.7 percent), and the highest reported rate since 1969 (CDC, 2006). These data are alarming given that LBW is one of the leading causes of infant morbidity and mortality in the United States (AECF, 2006). Infants that are born under 2500 grams are 5.5 times more likely to die in their first year and are also more likely to experience serious mental and physical health complications (Stein et al., 2006). Research has indicated that there are two factors that directly contribute to LBW, preterm birth (delivery before 37 weeks gestation) and intrauterine growth retardation (being born small for gestational age).
While there are multiple secondary factors that trigger preterm labor or intrauterine growth retardation, some of the leading factors include: smoking during pregnancy, infection, stress, maternal age, inadequate weight gain, and poor nutrition (MOD, 2007). Despite significant gains in determining some of the secondary risk factors for low birth weight, these factors fail to fully explain the social disparities that exist. For example, there are large disparities in low birth weight by race, socio-economic status, and access to prenatal services that continue to puzzle researchers. The purpose of this critical literature review is to examine the extent to which social factors such as SES, race, and access to prenatal care determine LBW as an outcome and to explore risk factors that might mediate the relationship between each social determinant and LBW as an outcome. The results indicated that SES, particularly income play a significant role in determining LBW. Furthermore, studies revealed that health care coverage is an important determinant of whether women access adequate prenatal care; however, whether these services decrease the risk of LBW still remains uncertain. Lastly, lifetime stress and racism emerged as two important explanations for the racial disparity in LBW between African Americans and White Americans.