Low birth weight in relation to the interval between pregnancies

Social Determinants of Premature Birth

Social determinants of health have received increasing attention in public health, leading to increased understanding of how social factors-individual and contextual-shape the health of the mother and infant. However, racial differences in birth outcomes persist, with incomplete explanation for the widening disparity. Here, we highlight the social determinants of preterm birth, with special attention to the social experiences among African American women, which are likely attributed to structural racism and discrimination throughout life.

Racial inequalities and perinatal health in the southeast region of Brazil

Few studies are available about racial inequalities in perinatal health in Brazil and little is known about whether the existing inequality is due to socioeconomic factors or to racial discrimination per se. Data regarding the Ribeirão Preto birth cohort, Brazil, whose mothers were interviewed from June 1, 1978 to May 31, 1979 were used to answer these questions. The perinatal factors were obtained from the birth questionnaire and the ethnic data were obtained from 2063 participants asked about self-reported skin color at early adulthood (23-25 years of age) in 2002/2004. Mothers of mulatto and black children had higher rates of low schooling (< or = 4 years, 27.2 and 38.0%) and lower family income (< or = 1 minimum wage, 28.6 and 30.4%). Mothers aged less than 20 years old predominated among mulattos (17.0%) and blacks (14.0%). Higher rates of low birth weight and smoking during pregnancy were observed among mulatto individuals (9.6 and 28.8%). Preterm birth rate was higher among mulattos (9.5%) and blacks (9.7%) than whites (5.5%). White individuals had higher rates of cesarean delivery (34.9%). Skin color remained as an independent risk factor for low birth weight (P < 0.001), preterm birth (P = 0.01), small for gestational age (P = 0.01), and lack of prenatal care (P = 0.02) after adjustment for family income and maternal schooling, suggesting that the racial inequalities regarding these indicators are explained by the socioeconomic disadvantage experienced by mulattos and blacks but are also influenced by other factors, possibly by racial discrimination and/or genetics.

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.

Maternal experiences of racism and violence as predictors of preterm birth: rationale and study design

Chronic psychological stress may raise the risk of preterm delivery by raising levels of placental corticotropin-releasing hormone (CRH). Women who have been the targets of racism or personal violence may be at particularly high risk of preterm delivery. The aims of this study are to examine the extent to which: (1) maternal experiences of racism or violence in childhood, adulthood, or pregnancy are associated with the risk of preterm birth; (2) CRH levels are prospectively associated with risk of preterm birth; and (3) CRH levels are associated with past and current maternal experiences of racism or violence. We have begun to examine these questions among women enrolled in Project Viva, a Boston-based longitudinal study of 6000 pregnant women and their children.

Differing birth weight among infants of U.S.-born blacks, African-born blacks, and U.S.-born whites

BACKGROUND

In the United States, the birth weights of infants of black women are lower than those of infants of white women. The extent to which the lower birth weights among blacks are related to social or genetic factors is unclear.

METHODS

We used vital records for 1980 through 1995 from Illinois to determine the distribution of birth weights among infants born to three groups of women -- U.S.-born blacks, African-born blacks, and U.S.-born whites.

RESULTS

The mean birth weight of 44,046 infants of U.S.-born white women was 3446 g, that of 3135 infants of African-born black women was 3333 g, and that of 43,322 infants of U.S.-born black women was 3089 g. The incidence of low birth weight (weight less than 2500 g) was 13.2 percent among infants of U.S.-born black women and 7.1 percent among infants of African-born black women, as compared with 4.3 percent among infants of U.S.-born white women (relative risks, 3.1 and 1.6, respectively). Among the women at lowest risk (those 20 to 39 years old, with 12 years of education for themselves and their spouses, early prenatal care, gravida 2 or 3, and no previous fetal loss), the rate of low birth weight in infants of African-born black women (3.6 percent) was closer to the rate in infants of U.S.-born white women (2.4 percent), and the rate in infants of U.S.-born black women remained high (7.5 percent).

CONCLUSIONS

The birth-weight patterns of infants of African-born black women and U.S.-born white women are more closely related to one another than to the birth weights of infants of U.S.-born black women.