Skip to main content


Log in

Prematurity and race account for much of the interstate variation in infant mortality rates in the United States

  • Article
  • Published:
Journal of Perinatology Submit manuscript



To assess the correlation between infant mortality and extreme prematurity by state.

Study design

This ecological study included data on 28,526,534 infants from 2007 to 2013 in all 50 US states and DC using CDC WONDER linked birth and infant death records. Regression analyses determined the correlation between infant and neonatal mortality rates and the proportion of extremely preterm, extremely low birth weight, and black births by state.


State infant and neonatal mortality rates were directly and highly correlated with the proportion of extremely preterm births (infant, r2 = 0.71, P < 0.001; neonatal, r2 = 0.77, P < 0.001) and extremely low birth weight births (r2 = 0.63, P < 0.001; r2 = 0.73, P < 0.001). The proportion of black births also correlated directly with infant and neonatal mortality rates.


Interstate variation in infant and neonatal mortality rates are primarily driven by rates of extremely preterm and extremely low birth weight births which is closely related to the proportion of black births.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1: Correlation of state infant mortality rates (IMR) and neonatal mortality rates (NMR) with the proportion of extremely low birth weight births (<1000 g).
Fig. 2: Correlation of infant mortality rates (IMR) and neonatal mortality rates (NMR) with the proportion of extremely preterm births by state.
Fig. 3: Correlation of infant and neonatal mortality rates with proportion of black births by state.

Similar content being viewed by others


  1. MacDorman MF, Mathews TJ, Mohangoo AD, Zeitlin J. International comparisons of infant mortality and related factors: United States and Europe, 2010. Natl Vital Stat Rep. 2014;63:1–6.

    PubMed  Google Scholar 

  2. Organization for Economic Co-operation and Development. Infant mortality rates “indicator”. 2019. Accessed 16 July 2019.

  3. Lorenz JM, Ananth CV, Polin RA, D’Alton ME. Infant mortality in the United States. J Perinatol. 2016;36:797–801.

    Article  CAS  Google Scholar 

  4. Mathews 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.

    Google Scholar 

  5. United States Department of Health and Human Services (US DHHS), Centers of Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics (DVS). Linked Birth/Infant Death Records 2007–2017, as compiled from data provided by the 57 vital statistics jurisdictions through the Vital Statistics Cooperative Program, on CDC WONDER On-line Database. Accessed 28 Aug 2019.

  6. Bass JL, Gartley T, Lyczkowski DA, Kleinman R. Trends in the Incidence of sudden unexpected infant death in the newborn: 1995-2014. J Pediatr. 2018;196:104–8.

    Article  Google Scholar 

  7. Ehrenthal DB, Wingate MS, Kirby RS. Variation by state in outcomes classification for deliveries less than 500 g in the United States. Matern Child Health J. 2011;15:42–8.

    Article  Google Scholar 

  8. Woods CR, Davis DW, Duncan SC, Myers JA, O’Shea TM. Variation in classification of live birth with newborn period death versus fetal death at the local level may impact reported infant mortality rate. BMC Pediatr. 2014;14:108.

    Article  Google Scholar 

  9. Hamilton BE, Martin JA, Osterman MJK, Curtin SC, Matthews TJ. Births: final data for 2014. Natl Vital Stat Rep. 2015;64:1–64.

    PubMed  Google Scholar 

  10. Lau C, Ambalavanan N, Chakraborty H, Wingate MS, Carlo WA. Extremely low birth weight and infant mortality rates in the United States. Pediatrics. 2013;131:855–60.

    Article  Google Scholar 

  11. Morse SB, Wu SS, Ma C, Ariet M, Resnick M, Roth J. Racial and gender differences in the viability of extremely low birth weight infants: a population-based study. Pediatrics. 2006;117:e106–12.

    Article  Google Scholar 

  12. Kramer MS, McLean FH, Boyd ME, Usher RH. The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations. JAMA. 1988;260:3306–8.

    Article  CAS  Google Scholar 

  13. Hagen EW, Sadek-Badawi M, Albanese A, Palta M. A comparison of Wisconsin neonatal intensive care units with national data on outcomes and practices. WMJ. 2008;107:320–6.

    PubMed  PubMed Central  Google Scholar 

  14. Cifuentes J, Bronstein J, Phibbs CS, Phibbs RH, Schmitt SK, Carlo WA. Mortality in low birth weight infants according to level of neonatal care at hospital of birth. Pediatrics. 2002;109:745–51.

    Article  Google Scholar 

  15. Lorch SA, Baiocchi M, Ahlberg CE, Small DS. The differential impact of delivery hospital on the outcomes of premature infants. Pediatrics. 2012;130:270–8.

    Article  Google Scholar 

  16. Rysavy MA, Li L, Bell EF, Das A, Hintz B, Stoll BJ, et al. Between-hospital variation in treatment and outcomes in extremely preterm infants. N Engl J Med. 2015;372:1801–11.

    Article  Google Scholar 

  17. Alleman BW, Bell EF, Li L, Dagle JM, Smith PB, Ambalavanan N, et al. Individual and center-level factors affecting mortality among extremely low birth weight infants. Pediatrics. 2013;132:175–84.

    Article  Google Scholar 

  18. Arzuaga BH, Meadow W. National variability in neonatal resuscitation practices at the limit of viability. Am J Perinatol. 2014;31:521–8.

    PubMed  Google Scholar 

  19. MacDorman MF, Mathews TJ. Recent trends in infant mortality in the United States. NCHS Data Brief. 2008;9:1–8.

    Google Scholar 

  20. Goyal NK, DeFranco E, Kamath-Rayne BD, Beck AF, Hall ES. County-level variation in infant mortality reporting at early previable gestational ages. Paediatr Perinat Epidemiol. 2017;31:385–91.

    Article  Google Scholar 

  21. Collins JW, David RJ, Simon DM, Prachand NG. Preterm birth among African American and white women with a lifelong residence in high-income Chicago neighborhoods: an exploratory study. Ethn Dis. 2007;17:113–7.

    PubMed  Google Scholar 

  22. Foster HW, Wu L, Brazekn MB. Intergenerational effects of high socioeconomic status on low birthweight and preterm birth in African Americans. J Natl Med Assoc. 2000;92:213–21.

    CAS  PubMed  PubMed Central  Google Scholar 

  23. Paul DA, Locke R, Zook K, Leef KH, Stefano JL, Colmorgen G. Racial differences in prenatal care of mothers delivering very low birth weight infants. J Perinatol. 2006;26:74–8.

    Article  CAS  Google Scholar 

  24. Nkansah-Amankra S, Luchok KJ, Hussey JR, Watkins K, Liu X. Effects of maternal stress on low birth weight and preterm birth outcomes across neighborhoods of South Carolina, 2000–2003. Matern Child Health J. 2010;14:215–26.

    Article  Google Scholar 

  25. Callaghan WM, MacDorman MF, Rasmussen SA, Qin C, Lackritz EM. The contribution of preterm birth to infant mortality in the United States. Pediatrics. 2006;118:1566–73.

    Article  Google Scholar 

  26. Conde-Agudelo A, Rosas-Bermúdez A, Kafury-Goeta AC. Birth spacing and risk of adverse perinatal outcomes: a meta-analysis. JAMA. 2006;295:1809–23.

    Article  CAS  Google Scholar 

  27. Romero R, Conde-Agudelo A, Da Fonseca E, O’Brien JM, Cetingoz E, Creasy GW, et al. Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data. Am J Obstet Gynecol. 2018;218:161–80.

    Article  CAS  Google Scholar 

  28. Alfirevic Z, Stampalija T, Medley N. Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy. Cochrane Database Syst Rev. 2017;6:CD008991.

    PubMed  Google Scholar 

  29. Roberts D, Brown J, Medley N, Dalziel SR. Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth. Cochrane Database Syst Rev. 2017;3:CD004454.

    PubMed  Google Scholar 

  30. Lumley J, Chamberlain C, Dowswell T, Oliver S, Oakley L, Watson L. Interventions for promoting smoking cessation during pregnancy. Cochrane Database Syst Rev. 2009;3:CD001055.

    Google Scholar 

  31. Iams JD, Romero R, Culhane JF, Goldenberg RL. Primary, secondary, and tertiary interventions to reduce the morbidity and mortality of preterm birth. Lancet. 2008;37:164–75.

    Article  Google Scholar 

Download references


Supported by the Perinatal Health and Human Development Research Program of the University of Alabama at Birmingham and the Children’s of Alabama Centennial Scholar Fund. The study sponsors did not participate in study design, data collection or analysis, writing of the paper, or the decision to submit the paper.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Colm P. Travers.

Ethics declarations

Conflict of interest

WAC is on the board of MEDNAX, Inc. The other authors declare that they have no conflict of interest.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Travers, C.P., Iannuzzi, L.A., Wingate, M.S. et al. Prematurity and race account for much of the interstate variation in infant mortality rates in the United States. J Perinatol 40, 767–773 (2020).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

  • Springer Nature America, Inc.

This article is cited by