Variations in Low Birth Weight and Preterm Delivery Among Blacks in Relation to Ancestry and Nativity: New York City, 1998 − 2002 David L. Howard, Susan S. Marshall, Jay S. Kaufman and David A. Savitz Pediatrics 2006;118;e1399 DOI: 10.1542/peds.2006-0665

University of North Carolina at Chapel Hill, North Carolina, United States
PEDIATRICS (Impact Factor: 5.47). 11/2006; 118(5):e1399-405. DOI: 10.1542/peds.2006-0665
Source: PubMed


Black women in the United States are more likely to give birth to preterm and low birth-weight infants than their white counterparts, but little is known about variation in birth outcomes within the black population. This study aimed to test the hypothesis that the risk of low birth weight and preterm birth within the black population varies by maternal ancestry and nativity.
We conducted a retrospective cohort study using New York City birth records. All of the recorded live births to black women occurring in New York City between January 1, 1998, and December 31, 2002 (N = 168,039), were divided into the following self-reported ancestry groups: African, American, Asian, Cuban, European, Puerto Rican, South and Central American (excluding Brazilian), and West Indian and Brazilian. To estimate adjusted risk ratios for low birth weight (weight at birth <2500 g) and preterm birth (gestational age at delivery <37 weeks, based on clinical estimate), we ran 3 models for each outcome, using negative binomial regression and Poisson regression with robust SE estimation. All of the models used blacks reporting American ancestry as the reference group. The first model included ancestry as the primary exposure variable along with covariates that included maternal age, parity, smoking, and education, as well as paternal education and race. Nativity (US- or foreign-born) was included in the second model, and terms representing interaction effects between ancestry and nativity were included in the third model.
There was substantial variation in risks of preterm birth and low birth weight among the black subgroups, with all of the groups having lower risks than the American black reference group, even after adjusting for maternal risk factors and other covariates. Risk ratios for low birth weight ranged from 0.55 among South/Central Americans to 0.91 among Cubans; risk ratios for preterm birth showed a similar pattern. Nativity was also associated with low birth weight and preterm birth; births to foreign-born women were less likely to be preterm or low birth weight than births to US-born women. Furthermore, nativity effects varied by ancestry group, with foreign-born status inversely associated with poor birth outcomes among South/Central Americans but not among West Indians/Brazilians.
Important health differences may be masked in studies that treat black women in America as a homogeneous group and do not take ethnic variation and nativity into account.

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    • "Such contrasting evidence may be explained by different access and referral to healthcare services [8,13,25], and by different integration policies in the host countries [11]. Better prognoses have been often explained also by the healthy migrant effect [23,26,27] and the epidemiological paradox - i.e. better perinatal outcomes among foreign-born women with demographic and socio-economic risk factors [27-29]. "
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    ABSTRACT: The number of immigrants has increased in Italy in the last twenty years (7.2% of the Italian population), as have infants of foreign-born parents, but scanty evidence on perinatal outcomes is available. The aim of this study was to investigate whether infants of foreign-born mothers living in Italy have different odds of adverse perinatal outcomes compared to those of native-born mothers, and if such measures changed over two periods. The source of this area-based study was the regional hospital discharge database that records perinatal information on all births in the Lazio region. We analysed 296,739 singleton births born between 1996-1998 and 2006-2008. The exposure variable was the mother's region of birth. We considered five outcomes of perinatal health. We estimated crude and adjusted odds ratios and 95% confidence intervals (CIs) to evaluate the association between mother's region of birth and perinatal outcomes. Perinatal outcomes were worse among infants of immigrant compared to Italian mothers, especially for sub-Saharan and west Africans, with the following crude ORs (in 1996-1998 and 2006-2008 respectively): 1.80 (95%CI:1.44-2.28) and 1.95 (95%CI:1.72-2.21) for very preterm births, and 1.32 (95%CI:1.16-1.50) and 1.32 (95%CI:1.25-1.39) for preterm births; 1.18 (95%CI:0.99-1.40) and 1.17 (95%CI:1.03-1.34) for a low Apgar score; 1.22 (95%CI:1.15-1.31) and 1.24 (95%CI:1.17-1.32) for the presence of respiratory diseases; 1.47 (95%CI:1.30-1.66) and 1.45 (95%CI:1.34-1.57) for the need for special or intensive neonatal care/in-hospital deaths; and 1.03 (95%CI:0.93-1.15) and 1.07 (95%CI:1.00-1.15) for congenital malformations. Overall, time did not affect the odds of outcomes differently between immigrant and Italian mothers and most outcomes improved over time among all infants. None of the risk factors considered confounded the associations. Our findings suggest that migrant status is a risk factor for adverse perinatal health. Moreover, they suggest that perinatal outcomes improved over time in some immigrant women. This could be due to a general improvement in immigrants' health in the past decade, or it may indicate successful application of policies that increase accessibility to mother-child health services during the periconception and prenatal periods for legal and illegal immigrant women in Italy.
    BMC Public Health 05/2011; 11(1):294. DOI:10.1186/1471-2458-11-294 · 2.26 Impact Factor
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    • "Nonetheless, the etiology of spontaneous preterm birth is still largely unknown [2]. Populations demonstrate widely varying risks of the outcome, but the specific genetic, dietary, behavioral or psychosocial factors that contribute to this variation remain obscure [3]. Researchers have described consistent socioeconomic patterns in preterm delivery risk in developed countries [4]. "
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    ABSTRACT: Birth before the 37th week of gestation (preterm birth) is an important cause of infant and neonatal mortality, but has been little studied outside of wealthy nations. Chile is an urbanized Latin American nation classified as "middle-income" based on its annual income per capita of about $6000. We studied the relations between maternal social status and neighborhood social status on risk of preterm delivery in this setting using multilevel regression analyses of vital statistics data linked to geocoded decennial census data. The analytic data set included 56,970 births from 2004 in the metropolitan region of Santiago, which constitutes about 70% of all births in the study area and about 25% of all births in Chile that year. Dimensionality of census data was reduced using principal components analysis, with regression scoring to create a single index of community socioeconomic advantage. This was modeled along with years of maternal education in order to predict preterm birth and preterm low birthweight. Births in Santiago displayed an advantaged pattern of preterm risk, with only 6.4% of births delivering before 37 weeks. Associations were observed between risk of outcomes and individual and neighborhood factors, but the magnitudes of these associations were much more modest than reported in North America. While several potential explanations for this relatively flat social gradient might be considered, one possibility is that Chile's egalitarian approach to universal prenatal care may have reduced social inequalities in these reproductive outcomes.
    BMC Pregnancy and Childbirth 11/2008; 8(1):46. DOI:10.1186/1471-2393-8-46 · 2.19 Impact Factor
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    • "Finally, the association between placental abruption and maternal race, especially abruption-associated PTB, prominent even after controlling for SES and maternal medical risk factors, may suggest the possibility of a genetic contribution along with environmental components to the pathogenesis of placental abruption. Self-reported race in general accurately reflects ancestry, but the heterogeneity of nativity in Black mothers have also been shown to influence birth outcomes [28,29]. Thus, self-reported race is a reasonable, but not perfect, correlate for ancestry and genetics. "
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    ABSTRACT: Efforts to elucidate risk factors for placental abruption are imperative due to the severity of complications it produces for both mother and fetus, and its contribution to preterm birth. Ethnicity-based differences in risk of placental abruption and preterm birth have been reported. We tested the hypotheses that race, after adjusting for other factors, is associated with the risk of placental abruption at specific gestational ages, and that there is a greater contribution of placental abruption to the increased risk of preterm birth in Black mothers, compared to White mothers. We conducted a population-based cohort study using the Missouri Department of Health's maternally-linked database of all births in Missouri (1989-1997) to assess racial effects on placental abruption and the contribution of placental abruption to preterm birth, at different gestational age categories (n = 664,303). Among 108,806 births to Black mothers and 555,497 births to White mothers, 1.02% (95% CI 0.96-1.08) of Black births were complicated by placental abruption, compared to 0.71% (95% CI 0.69-0.73) of White births (aOR 1.32, 95% CI 1.22-1.43). The magnitude of risk of placental abruption for Black mothers, compared to White mothers, increased with younger gestational age categories. The risk of placental abruption resulting in term and extreme preterm births (< 28 weeks) was higher for Black mothers (aOR 1.15, 95% CI 1.02-1.29 and aOR 1.98, 95% CI 1.58-2.48, respectively). Compared to White women delivering in the same gestational age category, there were a significantly higher proportion of placental abruption in Black mothers who delivered at term, and a significantly lower proportion of placental abruption in Black mothers who delivered in all preterm categories (p < 0.05). Black women have an increased risk of placental abruption compared to White women, even when controlling for known coexisting risk factors. This risk increase is greatest at the earliest preterm gestational ages when outcomes are the poorest. The relative contribution of placental abruption to term births was greater in Black women, whereas the relative contribution of placental abruption to preterm birth was greater in White women.
    BMC Pregnancy and Childbirth 10/2008; 8(1):43. DOI:10.1186/1471-2393-8-43 · 2.19 Impact Factor
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