Infant Mortality: An Overview of

Determinants and Prevention

Opportunities for Regions IV and VI

Ashley H. Schempf, PhDOffice of Epidemiology, Policy and Evaluation

Maternal and Child Health BureauHealth Resources and Services Administration,

DHHS

Outline• Basic epidemiology• Background• Data from 2004-2006 Period Linked Live

Birth / Infant Death File• Timing and Causes of Death• Contribution of Preterm Birth• Contribution of Racial Disparities

• Promising avenues for intervention

Background• Infant mortality is a sentinel

population health indicator

• Health of babies depends on the health of the population—not only mothers but fathers, families, and society

• US infant mortality rate (6.7 per 1,000 births)

• 28th among industrialized countries

• Recent plateau after long decline

Period of Death

Neonatal (<28 days)

• Comprise 2/3 of all deaths

• Driven by PTB/LBW, maternal/newborn health, risk-appropriate care

• Moderately preventable given current knowledge

Postneonatal (28-364 days)

• Comprise 1/3 of all deaths

• Driven by SIDS, injury, infection

• Highly preventable with current knowledge

67%

33%

Neonatal

Postneonatal

Infant Mortality by Period of Death

• Difference between Region IV and Other Regions is equally apportioned to excess neonatal and postneonatal mortality

• Difference between Region VI and the other regions is mostly postneonatal

U.S. Region IV Region VI Other Regions

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

4.55.3

4.4 4.3

2.3

2.9

2.62.0

PostneonatalNeonatal

Death

s p

er

1,0

00

8.2

6.8

7.0 6.

3

Leading Causes of DeathUnderlying Cause* Death Rate

Per 100,000% of

Deaths

Prematurity and related conditions 206.3 30.5%

Congenital anomalies 136.3 20.1%

SIDS/SUID 81.0 12.0%

Obstetric conditions 47.4 7.0%

External causes 36.5 5.4%

Perinatal infections 33.7 5.0%

Other infections 21.0 3.1%

Birth Asphyxia 11.1 1.6%

All other causes 103.9 15.3%

U.S. 2004-2006

*ICD-10 codes grouped by modified Dolfus classification scheme

What are the causes of excess infant death in

Regions IV and VI?Underlying Cause

Region IVRate

Ratio*

% of excess deaths

Region VIRate

Ratio*

% of excess deaths

Prematurity and related conditions 1.34 35% 0.97 -8%

Congenital anomalies 1.10 7% 1.16 31%

SIDS/SUID 1.53 20% 1.52 52%

External causes 1.49 8% 1.19 9%

Perinatal infections 1.39 6% 1.14 6%

Other infections 1.52 5% 1.30 8%

*Compared to all other regions; only causes contributing ≥5% shown

Preterm Birth

Gestational Age % of Births

% of Deaths IMR

<28 weeks 0.8% 46.2% 406.9

28-31 weeks 1.3% 8.5% 44.7

32,33 weeks 1.6% 3.9% 16.3

34-36 weeks 9.0% 9.8% 7.2

All preterm, <37 weeks

12.7% 68.3% 36.1

All term, 37+ weeks 87.3% 31.7% 2.4

U.S. 2004-2006

• About 2/3 of all deaths occur among preterm births• Almost half occur among those born <28 weeks

Late Preterm Birth• Accounts for ~10% of infant deaths• May be highly preventable• Largest component of PTB increase in

90’s• Preliminary data indicate 5%↓ 2006-

2009• IMR also has begun to decline again

• Promising Interventions• Physician/patient/hospital education to

reduce non-indicated late preterm / early term births• Ohio Perinatal Quality Collaborative

• March of Dimes Tool Kit

Racial DisparitiesU.S. Region IV Region VI Other

Regions

White IMR 5.7 6.3 6.4 5.4

Black IMR 13.5 14.0 13.1 13.3

Black-White Risk Ratio

2.4 2.2 2.0 2.5

Black-White Risk Difference

7.9 7.6 6.7 8.0

% Black Births 14% 25% 14% 11%

• Racial disparities are persistent and striking in every region• Somewhat lower in Regions IV and VI because of higher rates

among Whites (higher poverty is a key factor)• Excess infant mortality would remain even if disparity were

eliminated

What would happen if disparities were

eliminated?Current Levels

U.S. Region IV

Region VI

Other Regions

0.01.02.03.04.05.06.07.08.09.0

6.8

8.2

76.3

Black IMR = White IMR

0.0

2.0

4.0

6.0

8.0

10.0

5.7 6.3 6.15.4

Death

s p

er

1,0

00

=1.9

=0.8

Disparities explain 56% of the gap between Region IV and Other Regions

Determinants of Black-White Disparity

• 2/3 neonatal, 1/3 postneonatal• Neonatal contribution is driven by excess PTB,

particularly <28 weeks• Postneonatal contribution driven by SIDS,

injury, and infection; prematurity also increases vulnerability

• Excess PTB accounts for 80% of disparity, ~60% from 3 fold disparity at <28 weeks*

• Proximate causes: infection, vascular disorders• Distal determinants include lifecourse SES,

environment, stress/discrimination, intergenerational factors

* Schempf A, Branum A, Lukacs S, Schoendorf K. The Contribution of Preterm Birth to the Black-White Infant Mortality Gap: US, 1990 and 2000. American Journal of Public Health, 2007;97(7):1255-1260.

Guiding Frameworks/Resources

• Lifecourse/Multiple Determinants

• Perinatal Periods of Risk (PPOR)

• AMCHP State Infant Mortality Collaborative toolkit

Potential Avenues• Maternal health• Chronic conditions, obesity• Smoking

• Unintended pregnancy, birth spacing• Paternal involvement• SIDS/SUID preventionHealth Care Factors• Regionalization (Title V Indicator)• Health insurance (mothers and children)• Preventing non-indicated late preterm/early term

births• Preconception care, new models of care

CDC, Behavioral Risk Factor Surveillance System

Current Population Survey, Annual Social and Economic Supplement

Current Population Survey, Annual Social and Economic Supplement

MCHB, Title V Information System

AcknowledgementsMichael D. Kogan, PhD

Director, Office of Epidemiology, Policy and Evaluation

Cassie Lauver, ACSWDirector, Division of State and Community

Health

Peter C. van Dyck, MD, MS, MPHDirector, Maternal and Child Health Bureau