1. Recent Declines in Infant Mortality in the United States
Marian MacDorman, PhD and T.J. Mathews, MS
Division of Vital Statistics
National Center for Health Statistics

2. Vital Statistics Infant Mortality Data
Based on birth and death certificates filed in state vital statistics offices, and transmitted to NCHS.
National data files produced:
Birth (natality) data set – 2011 preliminary and 2010 final currently available
Main mortality file – 2011 preliminary and 2010 final currently available
Linked birth/infant death data set
Links birth and death certificate data for all infant deaths.
Purpose: To use more detailed data from the birth certificate for infant mortality analysis.
Currently available through 2008; 2009 expected by Jan. 2013

3. Infant, neonatal and postneonatal mortality rates, United States, 2000-2011
Source: NCHS linked birth/infant death data set, , mortality data set 2010, and preliminary mortality data set, 2011.

4. Percentage of preterm births: United States, 2000-2011
11.9
Source: Births: Final data for 2010; Births, preliminary data for 2011.

5. Percent distribution of births by gestational age, US, 2006 and 2010
Completed weeks of gestation
SOURCE: National Vital Statistics System, NCHS, CDC.

6. Infant mortality rate and percent of preterm births, US, 2000-2011
Source: CDC/NCHS; national vital statistics system

7. Infant mortality rates by gestational age, US, 2008
Completed weeks of gestation
Source: NCHS, linked birth/infant death data set.

8. Percent of births and infant deaths by gestational age (weeks), US, 2008
Source: CDC/NCHS Linked birth/infant death data set, 2008

9. Components of infant mortality
The overall infant mortality rate can be partitioned into two key components:
1. The distribution of births by gestational age;
2. Gestational age-specific infant mortality rates (i.e. the mortality rate for infants at a given gestational age)
Component 1 available through 2011; component 2 through 2008
Preliminary modeling suggests that both must have declined to yield the current infant mortality rate

10. Race/Ethnic Differences

11. Infant mortality rates by maternal race/ethnicity, US, 2008
Non American Puerto Total Mexican Non Cuban Central Asian or
Hispanic Indian Rican Hispanic or South Pacific
black white American Islander
Source: CDC/NCHS linked birth/infant death data set, 2008.

12. Percent contribution of two components to race and ethnic differences in infant mortality rates, 2007
Note: NHB=non-Hispanic black; NHW=non-Hispanic white; PR=Puerto Rican; AI=American Indian
Source: CDC/NCHS; linked birth/infant death data set

13. Infant mortality rates by race/ethnicity, US, 2000, 2005 and 2011
Source: Data from the vital statistics mortality file. Note: Infant mortality rates by
race and Hispanic origin are more accurate from the linked birth/infant death data set.

14. Percent of preterm births by maternal race/ethnicity, US, 2000, 2006, 2011

15. Trends in Leading Causes Of Infant Death

16. Infant mortality rates for the five leading causes of infant death in 2011: US, 2000, 2005, and 2011
10. The leading causes of infant death in 2007 were Congenital malformations, Disorders related to short gestation and low birthweight, not elsewhere classified, Sudden infant death syndrome or SIDS, Newborn affected by maternal complications of pregnancy, and unintentional injuries. From , infant mortality rates for three of the five leading causes actually increased. Both short gestation/low birthweight and maternal complications are closely linked to the US’s continuing problems with preterm births, and I will discuss this in more detail in a minute. For the unintentional injury category, part of the increase may be related to changes in the classification of sudden unexpected infant deaths. In other words, some deaths that might have formerly been certified as SIDS are now being certified to causes such as Accidental suffocation and strangulation in bed.
Source: NCHS, mortality data set data are ore preliminary.

17. State Differences

18. Infant mortality rates by State, 2010MT WY ID WA OR NV UT CA AZ ND SD NE CO NM TX OK KS AR LA MO IA MN WI IL IN KY TN MS AL GA FL SC NC VA WV OH MI NY PA MD DE NJ CT RI MA ME VT NH AK HI DC
5.00 to 5.99
Less than 5.00
6.00 to 6.99
7.00 to 7.99
More than 8.00
U.S. rate = 6.15
Source: National Vital Statistics System, NCHS, CDC

19. Decline in infant mortality rates by state, 2005-2010MT WY ID WA OR NV UT CA AZ ND SD NE CO NM TX OK KS AR LA MO IA MN WI IL IN KY TN MS AL GA FL SC NC VA WV OH MI NY PA MD DE NJ CT RI MA ME VT NH AK HI DC
U.S. change = -10.5
No significant change
Statistically significant decline of <20%
Statistically significant decline of 20% or more
Source: National Vital Statistics System, NCHS, CDC

20. Understanding the Recent Decline in Preterm Birth

21. Understanding the Recent Decline in Preterm Birth
Decline in preterm births from appears to be widespread. Declines in preterm rates for most/all:
- maternal race/ethnic groups
- maternal age groups
- states
- among both single and multiple births
Some factors to consider in changes to overall rate:
Recent decline in teen births (who have higher
preterm rates)
Leveling out of multiple birth rates
Changes in obstetrical management of pregnancy

22. Components of preterm birth
Spontaneous
preterm labor
40-45%
Source: Goldenberg et al. Lancet, 2008.

24. Percent preterm for cesarean, induced vaginal, and non-induced vaginal births: US, 2000, 2006, and 2010
Vaginal births

25. International Comparisons

26. Infant mortality rates, OECD countries, 2009
Source: Health, United States, OECD=Organization for Economic Cooperation and Development.

27. Percentage of preterm births, United States and selected European countries, 2004
Note: Excludes births at <22 weeks of gestation to promote comparability between countries. Preterm births are those from 22 to 36 weeks of gestation. Source: NCHS linked birth/infant death data set (for US data), and European Perinatal Health Report (for European data).

28. Conclusions
After a plateau from , the US infant mortality rate declined 12% from 2005 to 2011.
After more than two decades of increase, there was a 9% decrease in the preterm birth rate from
From , infant mortality declined most rapidly for non- Hispanic black women (-16%), followed by non-Hispanic white (-12%) and Hispanic women (-9%), based on mortality file data.
Infant mortality declines were largest for states such as Louisiana, Georgia, the Carolinas and DC with large African- American populations and which previously had persistently high infant mortality rates.
Provisional data from July 2011-June 2012 show a US infant mortality rate of 5.9, suggesting a continued downward trend from the rate of 6.05 in 2011.

29. Links to some recent reports
Infant mortality statistics from the linked birth/infant death data set:
Deaths, preliminary data for 2011:
Tables from Deaths, Final data for 2010:
Births, preliminary data for 2011:
Births: final data for 2010:
Provisional monthly and 12 month ending number of deaths, live births and infant deaths and rates: United States, January 2011 to June

30. Contact information
Marian MacDorman
T.J. Mathews
Any questions?