Background: Disparities exist in the rates of preterm birth and infant mortality across different racial/ethnic groups. However, only a few studies have examined the impact of race/ethnicity on the outcomes of premature infants. Objective: To report the rates of mortality and severe neonatal morbidity among multiple gestational age (GA) groups stratified by race/ethnicity. Methods: A retrospective cohort study utilizing linked birth certificate, hospital discharge, readmission, and death records up to 1 year of life. Live-born infants ≤36 weeks born in the period 2007-2012 were included. Maternal self-identified race/ethnicity, as recorded on the birth certificate, was used. ICD-9 diagnostic and procedure codes captured neonatal morbidities (intraventricular hemorrhage, retinopathy of prematurity, periventricular leukomalacia, bronchopulmonary dysplasia, and necrotizing enterocolitis). Multiple logistic regression was performed to evaluate the impact of race/ethnicity on mortality and morbidity, adjusting for GA, birth weight, sex, and multiple gestation. Results: Our cohort totaled 245,242 preterm infants; 26% were white, 46% Hispanic, 8% black, and 12% Asian. At 22-25 weeks, black infants were less likely to die than white infants (odds ratio [OR] 0.76; 95% confidence interval [CI] 0.62-0.94). However, black infants born at 32-34 weeks (OR 1.64; 95% CI 1.15-2.32) or 35-36 weeks (OR 1.57; 95% CI 1.00-2.24) were more likely to die. Hispanic infants born at 35-36 weeks were less likely to die than white infants (OR 0.66; 95% CI 0.50-0.87). Racial disparities at different GAs were also detected for severe morbidities. Conclusions: The impact of race/ethnicity on mortality and severe morbidity varied across GA categories in preterm infants. Disparities persisted even after adjusting for important potential confounders.

1.
Blencowe H, Cousens S, Oestergaard MZ, Chou D, Moller A-B, Narwal R, et al: National, regional, and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications. Lancet 2012;379:2162-2172.
2.
Matthews TJ, MacDorman MF, Thoma ME: Infant mortality statistics from the 2013 period-linked birth/infant death data set. Natl Vital Stat Rep 2015;64:1-30.
3.
Anderson JG, Baer RJ, Partridge JC, Kuppermann M, Franck LS, Rand L, et al: Survival and major morbidity of extremely preterm infants: a population-based study. Pediatrics 2016;138:e20154434.
4.
Stoll BJ, Hansen NI, Bell EF, Shankaran S, Laptook AR, Walsh MC, et al: Neonatal outcomes of extremely preterm infants from the NICHD Neonatal Research Network. Pediatrics 2010;126:443-456.
5.
Blumenshine P, Egerter S, Barclay CJ, Cubbin C, Braveman PA: Socioeconomic disparities in adverse birth outcomes: a systematic review. Am J Prev Med 2010;39:263-272.
6.
MacDorman MF: Race and ethnic disparities in fetal mortality, preterm birth, and infant mortality in the United States: an overview. Semin Perinatol 2011;35:200-208.
7.
Kitsantas P, Gaffney KF: Racial/ethnic disparities in infant mortality. J Perinat Med 2010;38:87-94.
8.
Hessol NA, Fuentes-Afflick E: Ethnic differences in neonatal and postneonatal mortality. Pediatrics 2005;115:e44-e51.
9.
Chen H-Y, Chauhan S, Rankins N, Ananth C, Siddiqui D, Vintzileos A: Racial and ethnic disparities in infant mortality in the United States: the role of gestational age. Amer J Perinatol 2013;30:469-476.
10.
Luke B, Brown MB: The changing risk of infant mortality by gestation, plurality, and race: 1989-1991 versus 1999-2001. Pediatrics 2006;118:2488-2497.
11.
Carter BM, Holditch-Davis D: Risk factors for necrotizing enterocolitis in preterm infants. Adv Neonatal Care 2008;8:285-290.
12.
Husain SM, Sinha AK, Bunce C, Arora P, Lopez W, Mun KS, et al: Relationships between maternal ethnicity, gestational age, birth weight, weight gain, and severe retinopathy of prematurity. J Pediatr 2013;163:67-72.
13.
Wallace ME, Mendola P, Kim SS, Epps N, Chen Z, Smarr M, et al: Racial/ethnic differences in preterm perinatal outcomes. Am J Obstet Gynecol 2017;216:306.e1-306.e12.
14.
American Medical Association: International Classification of Diseases: ICD-9-CM 2008. Chicago, American Medical Association, 2007.
15.
Jelliffe-Pawlowski LL, Norton ME, Baer RJ, Santos N, Rutherford GW: Gestational dating by metabolic profile at birth: a California cohort study. Am J Obstet Gynecol 2016;214:511.e1-511.e13.
16.
Steurer MA, Jelliffe-Pawlowski LL, Baer RJ, Partridge JC, Rogers EE, Keller RL: Persistent pulmonary hypertension of the newborn in late preterm and term infants in California. Pediatrics 2017;139:e20161165.
17.
Talge NM, Mudd LM, Sikorskii A, Basso O: United States birth weight reference corrected for implausible gestational age estimates. Pediatrics 2014;133:844-853.
18.
Tyson JE, Parikh NA, Langer J, Green C, Higgins RD: National Institute of Child Health and Human Development Neonatal Research Network: intensive care for extreme prematurity - moving beyond gestational age. N Engl J Med 2008;358:1672-1681.
19.
Perlman JM, Risser RC, Gee JB: Pregnancy-induced hypertension and reduced intraventricular hemorrhage in preterm infants. Pediatr Neurol 1997;17:29-33.
20.
Berman S, Richardson DK, Cohen AP, Pursley DM, Lieberman E: Relationship of race and severity of neonatal illness. Am J Obstet Gynecol 2001;184:668-672.
21.
Ross S, Naeye RL: Racial and environmental influences on fetal lung maturation. Pediatrics 1981;68:790-795.
22.
Bartick MC, Jegier BJ, Green BD, Schwarz EB, Reinhold AG, Stuebe AM: Disparities in breastfeeding: impact on maternal and child health outcomes and costs. J Pediatr 2017;181:49-55.e6.
23.
Ancel P-Y, Goffinet F, Kuhn P, Langer B, Matis J, Hernandorena X, et al: Survival and morbidity of preterm children born at 22 through 34 weeks' gestation in France in 2011. JAMA Pediatr 2015;169:230-239.
24.
Baumeister L, Marchi K, Pearl M, Williams R, Braveman P: The validity of information on “race” and “Hispanic ethnicity” in California birth certificate data. Health Serv Res 2000;35:869-883.
25.
Lorch SA, Kroelinger CD, Ahlberg C, Barfield WD: Factors that mediate racial/ethnic disparities in US fetal death rates. Am J Public Health 2012;102:1902-1910.
26.
Bonham VL, Callier SL, Royal CD: Will precision medicine move us beyond race? N Engl J Med 2016;374:2003-2005.
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