Skip to main content

Main menu

  • Home
  • Content
    • Current
    • Archive
    • Podcast: NC Health Policy Forum
    • Upcoming Scientific Articles
  • Info for
    • Authors
    • Reviewers
    • Advertisers
    • Subscribers
  • About Us
    • About the North Carolina Medical Journal
    • Editorial Board
  • More
    • Alerts
    • Feedback
    • Help
    • RSS
  • Other Publications
    • North Carolina Medical Journal

User menu

  • My alerts
  • Log in

Search

  • Advanced search
North Carolina Medical Journal
  • Other Publications
    • North Carolina Medical Journal
  • My alerts
  • Log in
North Carolina Medical Journal

Advanced Search

  • Home
  • Content
    • Current
    • Archive
    • Podcast: NC Health Policy Forum
    • Upcoming Scientific Articles
  • Info for
    • Authors
    • Reviewers
    • Advertisers
    • Subscribers
  • About Us
    • About the North Carolina Medical Journal
    • Editorial Board
  • More
    • Alerts
    • Feedback
    • Help
    • RSS
  • Follow ncmj on Twitter
  • Visit ncmj on Facebook
Research ArticlePolicy Forum

Running the Numbers

Disparities in Infant Mortality: Examining Perinatal Periods of Risk

Vito Di Bona, Kathleen Jones-Vessey and Sarah McCracken Cobb
North Carolina Medical Journal January 2020, 81 (1) 63-66; DOI: https://doi.org/10.18043/ncm.81.1.63
Vito Di Bona
statistician, State Center for Health Statistics, North Carolina Division of Public Health, NC Department of Health and Human Services, Raleigh, North Carolina
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: vito.dibona@dhhs.nc.gov
Kathleen Jones-Vessey
epidemiologist, Women's and Children's Health Section, North Carolina Division of Public Health, NC Department of Health and Human Services, Raleigh, North Carolina
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Sarah McCracken Cobb
project coordinator, Women's and Children's Health Section, North Carolina Division of Public Health, NC Department of Health and Human Services, Raleigh, North Carolina
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • References
  • Info & Metrics
  • PDF
Loading

The death of an infant in the first year of life is considered a sentinel public health event and an indicator of the overall health of a population. In 2017, approximately 7 infants died for every 1,000 infants born in North Carolina [1]. This was the 10th highest infant mortality rate in the nation in 2017, tied with Louisiana [2].

While the state has experienced substantial declines in overall infant mortality over the last 2 decades, racial disparities in infant mortality persist [3]. As shown in Figure 1, mortality rates for non-Hispanic white and Hispanic infants consistently fell below the state 5-year average over the last 2 decades, while non-Hispanic black and non-Hispanic American Indian infant mortality rates averaged 1.2 to 1.8 times higher than the state rate during the same time period.

FIGURE 1.
  • Download figure
  • Open in new tab
  • Download powerpoint
FIGURE 1.

Trends in Infant Mortality Rates, North Carolina Residents, 1998-2017

Comparing infant mortality rates among babies born to non-Hispanic black mothers with non-Hispanic white mothers, we can see that the disparity ratio remained virtually unchanged from 1998 to 2017, with non-Hispanic black infants having 5-year aggregate infant mortality rates 2.4 to 2.5 times higher than non-Hispanic white infants throughout this time period. Disparity ratios are also high among non-Hispanic American Indians, with rates 1.6 to 1.9 times higher than non-Hispanic white infants over the same period.

A variety of statewide health initiatives are focused on closing the black-white disparity ratio, including Healthy North Carolina 2020, the Perinatal Health Strategic Plan, and the North Carolina Early Childhood Action Plan [4-6]. Both Healthy North Carolina 2020 and the Early Childhood Action Plan aim to reduce the disparity in infant mortality rates between non-Hispanic white and non-Hispanic black infants to 1.92. Assuming the non-Hispanic white rate remained the same as in 2017 (5.0), the non-Hispanic black rate would need to decline another 23% to 9.6 deaths per 1,000 live births in order to achieve this statewide disparity goal.

Examining Perinatal Periods of Risk in North Carolina

The North Carolina State Center for Health Statistics recently initiated a Perinatal Periods of Risk (PPOR) study to provide more information about the disparities in infant mortality rates. The PPOR analytic approach is a 2-phase methodology examining age at death and birth weight to map mortality rates, identify excess mortality, and suggest possible areas for intervention [7-9]. One of the strengths of the PPOR analytic approach is that when fetal-infant mortality is partitioned into 4 periods of risk defined by birth weight and age at time of death, the preventive factors and strategies for consideration can be narrowed and resources targeted to periods of greatest need.

Using Vital Statistics data from the State Center for Health Statistics, PPOR classifies fetal-infant deaths into 4 periods of risk. The Maternal Health/Prematurity period of risk includes all fetal and infant deaths of 500-1,499g and ≥24 weeks for gestation. The Maternal Care period of risk includes fetal deaths of 1,500g or more and ≥24 weeks. The Newborn Care period of risk includes infant deaths of 1,500g or more and <28 days of age. The Infant Health period of risk includes infant deaths of 1,500g or more and ≥28 days of age. These 4 periods of risk can be arranged schematically into a PPOR Mortality Map as shown in Figure 2.

FIGURE 2.
  • Download figure
  • Open in new tab
  • Download powerpoint
FIGURE 2.

Perinatal Periods of Risk Mortality Map

The first phase of PPOR analysis identifies excess mortality by comparing fetal-infant mortality rates from a reference group with relatively low mortality rates to the higher mortality rates of the other study groups. The underlying premise of the PPOR approach is that the comparison groups should be able to achieve low mortality rates similar to those of the reference group. The reference population for the North Carolina PPOR analysis consists of infants born to non-Hispanic white women aged 21 years and older and with more than 12 years of education. Separate PPOR Mortality Maps are created for non-Hispanic American Indian, non-Hispanic white, non-Hispanic black, and Hispanic infants and then compared with the Mortality Map of the reference population to determine the excess mortality rate for each risk period and the number of excess deaths.

The data used for the North Carolina PPOR analysis are derived from information collected on North Carolina resident vital records from 2014 to 2017, including fetal death certificates and infant death certificates linked with birth certificate records. The analytic dataset was determined to be of sufficient size and quality for PPOR analysis and retained 481,388 birth records, 1,923 fetal death records, and 2,427 infant death records.

As shown in Table 1, there were 4,350 fetal and infant deaths in North Carolina during 2014-2017, and a total fetal-infant mortality rate of 9.0 deaths per 1,000 live births and fetal deaths as compared to the rate of the reference group of 5.87 per 1,000. Within all 4 periods of risk, non-Hispanic black infants have higher fetal-infant mortality than the other race/ethnicity study groups and—apart from the reference group—Hispanic infants have lower mortality in every risk period. For all study groups, the Maternal Health/Prematurity period has the highest fetal-infant mortality rate, and the Newborn Care period has the lowest. However, there are differences between groups in how mortality is distributed among the periods of risk. For non-Hispanic black infants, over 43% and 19% of deaths occur within the Maternal Health/Prematurity and Infant Health periods, respectively. This result is in contrast to the 30% and 29% of deaths of non-Hispanic white infants born to mothers not in the reference group during those same periods of risk.

View this table:
  • View inline
  • View popup
  • Download powerpoint
TABLE 1.

Rates (Frequency) of Fetal-Infant Mortality and Excess Mortality by Race and Ethnicity, North Carolina Residents, 2014-2017

Table 1 also presents excess fetal-infant mortality rates and excess deaths for the study groups. The excess mortality rate is calculated as the difference between the rate of the reference population and that of the study group, and the number of excess deaths for a risk period is calculated as the product of the excess mortality rate and the number of births and fetal deaths in the subgroup. Non-Hispanic black infants had the highest excess mortality rates across all risk periods and account for more than half of the total excess deaths in the state (968 excess deaths) during the study period. The overall excess mortality rate for non-Hispanic black infants is approximately 60% higher than the rate for non-Hispanic whites, and Maternal Health/Prematurity is the period of risk with the highest excess mortality rate. The proportion of excess mortality contributed by each risk period also varied by race/ethnicity study group. Excess fetal-infant deaths occurring within the Maternal Health/Prematurity period of risk make up half or more of all excess deaths of non-Hispanic black and Hispanic infants while for non-Hispanic white infants, the 41% of excess deaths within the Infant Health period of risk make up the largest contribution. In 2017, among non-Hispanic black infants, the leading causes of death in the Infant Health period included birth defects and ill-defined causes such as Sudden Unexpected Infant Death (SUID) [1].

Results from the North Carolina PPOR analysis showing racial disparities in reported fetal-infant mortality rates are consistent with other results found in the published literature [9, 10]. As is the case for infant mortality rates, the fetal-infant mortality rates for non-Hispanic black infants are greater than rates for other groups. Further, non-Hispanic black infants account for well over half of excess fetal-infant deaths in the state. There is a developing body of literature that suggests racial discrimination may be driving some of these disparities [11, 12]. Despite generally lower levels of maternal educational attainment and later initiation of prenatal care, Hispanic infants have fetal-infant mortality rates similar to that of the reference group and few excess deaths reported during the study period—an example of the well-documented “Hispanic Paradox” [13]. Though the study groups were primarily defined by race and ethnicity, non-Hispanic white infants were split into 2 groups defined by maternal educational attainment and maternal age. Non-Hispanic whites who were not members of the reference population had higher rates of mortality and were about twice as likely to die in the first year of life as those in the reference group. While it is not clear which characteristics of this group are driving this disparity, this finding reinforces that social and environmental determinants apart from race exert a considerable influence on fetal-infant mortality.

By stratifying the population by race and ethnicity for the PPOR Phase 1 analysis, results can be used to further tailor interventions to meet the specific needs of subpopulations. For example, knowing that in North Carolina, among non-Hispanic black and Hispanic infants, the majority of excess deaths occurred in the Maternal Health/Prematurity period means that interventions that address preconception care might have the most impact for these groups. The North Carolina State Center for Health Statistics is currently completing the second phase of the PPOR analysis, which will systematically investigate excess mortality to determine the risk factors and prevention measures that will be most effective in reducing overall fetal-infant mortality rates.

Acknowledgments

Potential conflicts of interest. The authors have no relevant conflicts of interest.

  • ©2020 by the North Carolina Institute of Medicine and The Duke Endowment. All rights reserved.

References

  1. ↵
    1. State Center for Health Statistics
    2017 Infant Mortality Statistics for North Carolina. North Carolina Department of Health and Human Services website. schs.dph.ncdhhs.gov/data/vital/ims/2017/. Accessed August 29, 2019.
  2. ↵
    1. National Center for Health Statistics
    Stats of the States: 2017 Infant Mortality Rates by State. CDC website. www.cdc.gov/nchs/pressroom/sosmap/infant_mortality_rates/infant_mortality.htm. Accessed August 29, 2019.
  3. ↵
    1. Watkins S,
    2. Avery M
    North Carolina Infant and Child Fatality Update 2018. Presentation to the North Carolina Child Fatality Task Force. Raleigh, NC: North Carolina Child Fatality Task Force; 2018. https://www.ncleg.gov/DocumentSites/Committees/NCCFTF/Presentations/2018-2019/Child%20Fatality%202017%20data_Final10-29-18corrected.pdf. Accessed October 9, 2019.
  4. ↵
    1. North Carolina Institute of Medicine
    Healthy North Carolina 2020: A Better State of Health. Morrisville, NC: North Carolina Institute of Medicine; 2011. https://publichealth.nc.gov/hnc2020/docs/HNC2020-FINAL-March-revised.pdf Accessed August 29, 2019.
  5. Women's and Children's Health Section. N.C. Perinatal Health Strategic Plan: 2016-2020. North Carolina Department of Health and Human Services website. whb.ncpublichealth.com/phsp/. Accessed August 29, 2019.
  6. ↵
    Women's and Children's Health Section. Early Childhood Action Plan. North Carolina Department of Health and Human Services website. www.ncdhhs.gov/about/department-initiatives/early-childhood/early-childhood-action-plan. Accessed August 29, 2019.
  7. ↵
    1. Sappenfield WM,
    2. Peck MG,
    3. Gilbert CS,
    4. Haynatzka VR,
    5. Bryant T
    Perinatal periods of risk: analytic preparation and phase 1 analytic methods for investigating feto-infant mortality. Matern Child Health J. 2010;14(6):838-850.
    OpenUrlPubMed
    1. Peck MG,
    2. Sappenfield WM,
    3. Skala J
    Perinatal periods of risk: a community approach for using data to improve women and infants' health. Matern Child Health J. 2010;14(6):864-874.
    OpenUrlCrossRefPubMed
  8. ↵
    1. Sappenfield WM,
    2. Peck MG,
    3. Gilbert CS,
    4. Haynatzka VR,
    5. Bryant T
    Perinatal periods of risk: phase 2 analytic methods for further investigating feto-infant mortality. Matern Child Health J. 2010;14(6):851-863.
    OpenUrlCrossRefPubMed
  9. ↵
    1. Mittal M
    Perinatal Periods of Risk (PPOR): A Useful Tool for Analyzing Fetal and Infant Mortality: SCHS Statistical Brief #28. Raleigh, NC: State Center for Health Statistics, Department of Public Health; 2005. https://schs.dph.ncdhhs.gov/schs/pdf/SB28.pdf. Accessed May 23, 2018.
  10. ↵
    1. Alhusen JL,
    2. Bower K,
    3. Epstein E,
    4. Sharps P
    Racial discrimination and adverse birth outcomes: an integrative review. J Midwifery Womens Health. 2016;61(6):707-720.
    OpenUrl
  11. ↵
    1. David R,
    2. Collins J
    Disparities in infant mortality: what's genetics got to do with it? Am J Public Health. 2007;97(7):1191-1197.
    OpenUrlCrossRefPubMed
  12. ↵
    1. Franzini L,
    2. Ribble JC,
    3. Keddie AM
    Understanding the Hispanic health paradox. Ethnic Dis. 2001;11(3):496-518.
    OpenUrlPubMed
PreviousNext
Back to top

In this issue

North Carolina Medical Journal: 81 (1)
North Carolina Medical Journal
Vol. 81, Issue 1
January-February 2020
  • Table of Contents
  • Index by author
Print
Download PDF
Email Article

Thank you for your interest in spreading the word on North Carolina Medical Journal.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Running the Numbers
(Your Name) has sent you a message from North Carolina Medical Journal
(Your Name) thought you would like to see the North Carolina Medical Journal web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
6 + 0 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.
Citation Tools
Running the Numbers
Vito Di Bona, Kathleen Jones-Vessey, Sarah McCracken Cobb
North Carolina Medical Journal Jan 2020, 81 (1) 63-66; DOI: 10.18043/ncm.81.1.63

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
Running the Numbers
Vito Di Bona, Kathleen Jones-Vessey, Sarah McCracken Cobb
North Carolina Medical Journal Jan 2020, 81 (1) 63-66; DOI: 10.18043/ncm.81.1.63
del.icio.us logo Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Examining Perinatal Periods of Risk in North Carolina
    • Acknowledgments
    • References
  • Figures & Data
  • Info & Metrics
  • References
  • PDF

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • Maternal and Infant Mortality in North Carolina
  • The State of North Carolina's Perinatal Health
  • Google Scholar

More in this TOC Section

Policy Forum

  • Health Policy Gets Personal
  • Breaking the Cycle
  • Breaking the Cycle
Show more Policy Forum

DEPARTMENTS

  • COVID-19 Reflections: COVID-19 Vaccination in North Carolina: Promoting Equity by Partnering with Communities and Health Care Providers
  • COVID-19 Reflections: We Are Not OK: Safety Net Primary Care Access in a Non-Expansion State Amid COVID-19
  • Focus on Philanthropy: How The John Rex Endowment Helped Fund Healthier Places in Wake County
Show more DEPARTMENTS

Similar Articles

About & Contact

  • About the NCMJ
  • Editorial Board
  • Feedback

Info for

  • Advertisers
  • Authors
  • Reviewers
  • Subscribers

Articles & Alerts

  • Archive
  • Current Issue
  • Get Alerts
  • Upcoming Articles

Additional Content

  • Current NCIOM Task Forces
  • NC Health Data & Resources
  • NCIOM Blog
North Carolina Medical Journal

ISSN: 0029-2559

© 2022 North Carolina Medical Journal

Powered by HighWire