Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Understanding the relative contributions of prematurity and congenital anomalies to neonatal mortality



To examine the relative contributions of preterm delivery and congenital anomalies to neonatal mortality.

Study design

Retrospective analysis of 2009–2011 linked birth cohort-hospital discharge files for California, Missouri, Pennsylvania and South Carolina. Deaths were classified by gestational age and three definitions of congenital anomaly: any ICD-9 code for an anomaly, any anomaly with a significant mortality risk, and anomalies recorded on the death certificate.


In total, 59% of the deaths had an ICD-9 code for an anomaly, only 43% had a potentially fatal anomaly, and only 34% had a death certificate anomaly. Preterm infants (<37 weeks GA) accounted for 80% of deaths; those preterm infants without a potentially fatal anomaly diagnosis comprised 53% of all neonatal deaths. The share of preterm deaths with a potentially fatal anomaly decreases with GA.


Congenital anomalies are responsible for about 40% of neonatal deaths while preterm without anomalies are responsible for over 50%.

This is a preview of subscription content

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1


  1. MacDorman MF, Rosenberg HM. Trends in infant mortality by cause of death and other characteristics, 1960-88. Vital Health Stat. 1993;20:1–57.

    Google Scholar 

  2. Ely DM, Driscoll AK. Infant mortality in the United States, 2017: data from the period linked birth/infant death file. Natl Vital Stat Rep. 2019;68:1–20.

    PubMed  Google Scholar 

  3. Williams RL, Chen PM. Identifying the sources of the recent decline in perinatal mortality rates in California. N Engl J Med. 1982;306:207–14.

    CAS  Article  Google Scholar 

  4. Horbar JD, Badger GJ, Carpenter JH, Fanaroff AA, Kilpatrick S, LaCorte M, et al. Trends in mortality and morbidity for very low birth weight infants, 1991-1999. Pediatrics. 2002;110:143–51.

    Article  Google Scholar 

  5. Ely DM, Hoyert DL. Differences between rural and urban areas in mortality rates for the leading causes of infant death: United States, 2013–2015. NCHS Data Brief. 2018:1–8.

  6. Hexter AC, Harris JA. Bias in congenital malformations information from the birth certificate. Teratology. 1991;44:177–80.

    CAS  Article  Google Scholar 

  7. Shah KP, deRegnier RO, Grobman WA, Bennett AC. Neonatal mortality after interhospital transfer of pregnant women for imminent very preterm birth in Illinois. JAMA Pediatr. 2020;174:358–65.

    Article  Google Scholar 

  8. Shrestha M, Scarpino SV, Edwards EM, Greenberg LT, Horbar JD. The interhospital transfer network for very low birth weight infants in the United States. EPJ Data Sci. 2018;7:1–14.

    Article  Google Scholar 

  9. Phibbs CS, Baker LC, Caughey AB, Danielsen B, Schmitt SK, Phibbs RH. Level and volume of neonatal intensive care and mortality in very-low-birth-weight infants. N Engl J Med. 2007;356:2165–75.

    CAS  Article  Google Scholar 

  10. Lorch S, Baiocchi M, Ahlberg C, Small D. The differential impact of delivery hospital on the outcomes of premature infants. Pediatrics. 2012;130:270–8.

    Article  Google Scholar 

  11. Herrchen B, Gould JB, Nesbitt TS. Vital statistics linked birth/infant death and hospital discharge record linkage for epidemiological studies. Comput Biomed Res. 1997;30:290–305.

    CAS  Article  Google Scholar 

  12. Hexter AC, Harris JA, Roeper P, Croen LA, Krueger P, Gant D. Evaluation of the hospital discharge diagnoses index and the birth certificate as sources of information on birth defects. Public Health Rep. 1990;105:296–307.

    CAS  PubMed  PubMed Central  Google Scholar 

Download references


Partial support by the March of Dimes Prematurity Research Center at Stanford University School of Medicine (to CSP and SKS); the Eunice Kennedy Shriver National Institute of Child Health and Human Development (RO1 HD084819 [to CSP, MP, SKS, and SAL].

Author information

Authors and Affiliations



CSP and SAL were co-PIs for the grant that provided funding, conceived of the idea for this study, designed the analysis, supervised the data analysis, interpreted the results, contributed to the framing of the manuscript, and contributed to the revisions to the manuscript. CSP drafted the initial version of the manuscript. MP and SKS were the analysts that actually created the study datasets and conducted the analyses. They provided critical input into the design of the analyses and contributed to the revisions of the manuscript. JAR helped refine the analysis plan and the interpretation of the results, and contributed to the framing of the manuscript and revisions of the manuscript. All authors approved the final version of the manuscript before it was submitted.

Corresponding author

Correspondence to Ciaran S. Phibbs.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information


Appendix Table A-1: Definitions of the Categories of Congenital Anomalies with a Significant Association with Neonatal Mortality

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Phibbs, C.S., Passarella, M., Schmitt, S.K. et al. Understanding the relative contributions of prematurity and congenital anomalies to neonatal mortality. J Perinatol 42, 569–573 (2022).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


Quick links