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The letters by Moultrie and Spriggs state that our manuscript1Kistka Z.A.-F. Palomar L. Lee K.A. et al.Racial disparity in the frequency of recurrence of preterm birth.Am J Obstet Gynecol. 2007; 196: 131.e1-131.e6Abstract Full Text Full Text PDF Scopus (167) Google Scholar concluded that “genetics is the cause of racial disparities” in preterm birth and “racial disparities in preterm birth must be due to an underlying genetic factor.” Implicit in this misrepresentation of our results is the notion that we assert that there is no role for social and environmental factors. We present information that many social and environmental factors indeed contribute to risk for preterm birth, and these factors may not be equally distributed across races. Nonetheless, after adjusting for many of these factors, including maternal education as indicated in our regression analysis, a large increase in risk for preterm births in blacks remains. This result, taken together with the increase in risk of recurrence, concordant gestational age timing, and earlier preterm births along with recent genetic studies from other groups,2Simhan H.N. Krohn M.A. Roberts J.M. Zeevi A. Caritis S.N. Interleukin-6 promoter −174 polymorphism and spontaneous preterm birth.Am J Obstet Gynecol. 2003; 189: 915-918Abstract Full Text Full Text PDF PubMed Scopus (109) Google Scholar, 3Wang H. Parry S. Macones G. et al.A functional SNP in the promoter of the SERPINH1 gene increases risk of preterm premature rupture of membranes in African Americans.Proc Natl Acad Sci USA. 2006; 103: 13463-13467Crossref PubMed Scopus (80) Google Scholar suggests genetic factors contribute to the racial disparity. We explicitly state in our paper that we have not proven a genetic cause, but accumulating information suggests a component of the increase in risk is likely to be heritable. Data from immigrant studies highlight the complexity of factors that have an impact on risk for preterm birth. However, those studies that have analyzed preterm birth in foreign vs US-born black cohorts consistently demonstrate an increase in risk for blacks above whites, including foreign-born blacks.4Acevedo-Garcia D. Soobader M.J. Berkman L.F. The differential effect of foreign-born status on low birth weight by race/ethnicity and education.Pediatrics. 2005; 115: e20-e30PubMed Google Scholar, 5David R.J. Collins Jr, J.W. Differing birth weight among infants of U.S.-born blacks, African-born blacks, and U.S.-born whites.N Engl J Med. 1997; 337: 1209-1214Crossref PubMed Scopus (371) Google Scholar, 6Howard D.L. Marshall S.S. Kaufman J.S. Savitz D.A. Variations in low birth weight and preterm delivery among blacks in relation to ancestry and nativity: New York City, 1998-2002.Pediatrics. 2006; 118: e1399-e1405Crossref PubMed Scopus (81) Google Scholar Curiously, Fang et al7Fang J. Madhavan S. Alderman M.H. Low birth weight: race and maternal nativity—impact of community income.Pediatrics. 1999; 103: E5Crossref PubMed Scopus (91) Google Scholar adjusted for preterm birth in their regression analysis of nativity on low-birthweight, confounding the interpretation of their results, given the consistent increase in preterm birth risk among blacks. To say that race is purely a social construct ignores a wealth of information on ancestry-dependent genomic variation and accuracy of self-reported race as reflecting ancestry, which should be brought to bear on the problem of preterm birth.8Jorde L.B. Wooding S.P. Genetic variation, classification and “race.”.Nat Genet. 2004; 36: S28-S33Crossref PubMed Scopus (412) Google Scholar, 9Tang H. Quertermous T. Rodriguez B. et al.Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies.Am J Hum Genet. 2005; 76: 268-275Abstract Full Text Full Text PDF PubMed Scopus (427) Google Scholar Multidisciplinary approaches to preterm birth (analyzing social factors as can be accomplished through immigrant studies or stress pathways, for example) will continue to produce valuable information. We encourage the broad research community interested in preterm birth to remain open minded and collect some DNA along the way. Psychosocial contributors to preterm birth must be consideredAmerican Journal of Obstetrics & GynecologyVol. 197Issue 3PreviewThe attribution by Kistka et al1 that genetics is the cause of racial disparities is lacking in credibility, given the substantial amount of research suggesting that social factors contribute to the racial/ethnic disparities in birth outcomes. Race is a social construct, so to attribute a health outcome to race without assessing the social implications of the construct gives more credence to a biological definition of race. Furthermore, attributing racial disparities to genetics suggests that all blacks, regardless of nationality, should have similar birth outcomes. Full-Text PDF