The preceding chapter reviewed the association between individual-level health behaviors and psychosocial characteristics and the risk of preterm birth. In general, studies have not revealed the individual-level risk factors that are strongly and consistently associated with the risk of preterm birth. However, the literature on racial and ethnic disparities in the rates of preterm birth suggests other individual-level characteristics that may be associated with preterm birth and that should be considered. For example, African American women are disproportionately affected by many individual-level conditions that may be associated with preterm birth, such as the higher likelihood of being unmarried, of having lower levels of income and education, and of having poorer prepregnancy health than white women. Thus, it is important to also consider sociodemographic characteristics in relation to preterm birth. These individual-level factors do not occur in isolation. They are embedded in a social context, which also has implications for preterm birth. This chapter addresses both of these issues. The first section addresses sociodemographic characteristics, such as maternal age, marital status and cohabitation, race and ethnicity, and socioeconomic condition. The second section discusses the association between neighborhood conditions and the potential mechanisms through which the neighborhood context may influence reproductive outcomes.

A number of maternal sociodemographic characteristics are associated with an increased risk for preterm birth. This section evaluates the relationships between maternal age, marital status and cohabitation, race and ethnicity, and socioeconomic condition and preterm birth. Possible causes of racial-ethnic and socioeconomic disparities in preterm birth are also explored.

Several studies have identified young maternal age as an important risk factor for preterm birth (Amini et al., 1996; Branum and Schoendorf, 2005; Fraser et al., 1995; Hediger et al., 1997; Satin et al., 1994; Scholl et al., 1992, 1994). Hediger et al. (1997) found that young adolescents (less than