Preterm birth among African American and white women with a lifelong residence in high-income Chicago neighborhoods: an exploratory study.

OBJECTIVE: To explore the association between race and preterm birth among women with a lifelong residence in high-income neighborhoods. METHODS: Stratified and multivariable logistic regression analyses were performed on the Illinois transgenerational birthfile (infants born 1989-1991 and mothers born 1956-1975) with appended US Census income data. African American (n = 777) and non-Hispanic White (n = 2,327) infants born to mothers with a lifelong residence in Chicago census tracts with median family incomes in the top income quartile were studied. RESULTS: African Americans had a twofold greater preterm (< 37 weeks) birth rate than Whites: 11.6% vs 5.2%, relative risk (95% confidence interval) equaled 2.2 (1.7-2.9). The adjusted (controlling for maternal birth weight, age, education, marital status, cigarette smoking, and prenatal care utilization) odds ratio of preterm birth for African Americans (compared to Whites) equaled 1.2 (.4-2.0). African Americans had a sixfold greater very low birth weight rate (< 1500 g) than Whites: 3.3% vs .6%: relative risk (95% confidence interval) equaled 5.9 (3.1-11.2). The adjusted odds ratio of very low birth weight for African Americans (compared to Whites) equaled 2.4 (1.1-3.9). CONCLUSIONS: A stark racial disparity in the unadjusted rates of preterm birth and very low birth weight exists among women with a lifelong residence in high-income urban neighborhoods; however, the disparity narrows when traditional, individual-level risk factors are mathematically controlled.

Advancing maternal age and infant birth weight among urban African Americans: the effect of neighborhood poverty.

OBJECTIVE: This study sought to determine whether neighborhood poverty modifies the relationship between maternal age and infant birth weight among urban African Americans. DESIGN: Stratified analyses were performed on the vital records of African Americans born in Chicago by means of 1992-1995 computerized birth file with appended 1990 US Census income and 1995 Chicago Department of Public Health data. Four neighborhood-level variables (low median family income, high rates of unemployment, homicide, and lead poisoning) were analyzed. SETTING: This is a population-based study. RESULTS: Twenty-one percent (n=21,811) of women resided in nonimpoverished neighborhoods (zero ecologic risk factors); 23% (n=24,914) of women lived in extremely impoverished neighborhoods (four ecologic risk factors). In nonimpoverished neighborhoods, 30-34 year old women had a moderately low birth weight (1500-2499 g) rate of 13.9% compared to 10.3% for women aged 20-24 years; risk difference (95% confidence interval [CI])=3.5 (2.2-4.6). In contrast, extremely impoverished women aged 30-34 years had a moderately low birth weight rate of 19.8% compared to 11.8% for women aged 20-24 years; risk difference (95% CI)=7.7 (6.1-9.3). This trend persisted among women who received early prenatal care and were primagravids or of low parity. Neighborhood poverty did not modify the association of advancing maternal age and the risk of very low birth weight (<1500 g). CONCLUSIONS: Neighborhood poverty accelerates the rise in moderately low birth weight but not very low birth weight; rates were associated with advancing maternal age among urban African Americans.

Relation of maternal low birth weight to infant growth retardation and prematurity.

OBJECTIVES: This study sought to determine the relationship between maternal birth weight, infant intrauterine growth retardation, and prematurity. METHODS: Stratified and logistic regression analyses were performed on a dataset of computerized Illinois vital records of African American (N = 61,849) and White (N = 203,698) infants born between 1989 and 1991 and their mothers born between 1956 and 1975. RESULTS: Race-specific rates of small-for-gestational age (weight-for-gestational age <10th percentile) and preterm (<37 weeks) infants rose as maternal birth weight declined. The adjusted (controlling for maternal age, education, marital status, parity, prenatal care utilization, and cigarette smoking) odds ratio (95% confidence interval) of small-for-gestational age for maternal low birth weight (<2,500 g) among African Americans and Whites were 1.7 (1.1.4-1.9) and 1.8 (1.7-2.0), respectively. The adjusted odds ratio (95% confidence interval) of prematurity for maternal low birth weight (<2,500 g) among African Americans and Whites were 1.6 (1.3-1.9) and 1.3 (1.0-1.6), respectively. The racial disparity in the rates of small-for-gestational age and prematurity persisted independent of maternal birth weight: adjusted odds ratio equaled 2.2 (2.1-2.4) and 1.5 (1.4-1.7), respectively. CONCLUSIONS: Maternal low birth weight is a risk factor for infant intrauterine growth retardation and prematurity among African Americans independent of maternal risk status during pregnancy; it is a risk factor for infant intrauterine growth retardation among Whites. Maternal low birth weight fails to explain the racial disparity in the rates of small-for-gestational age and premature infants.