Infant Mortality: Trends and Disparities

Marian MacDorman and T.J. MathewsDivision of Vital Statistics

National Center for Health Statistics

Presented to the Secretary’s Advisory Committee on Infant Mortality

March 26, 2015

Vital Statistics Infant Mortality Data• Based on all birth and death certificates filed in state vital

statistics offices, and transmitted to NCHS.

• National data files currently available: – Birth (natality) data – 2013 final

– Mortality data – 2013 final

– Fetal death data – 2012 final

– Linked birth/infant death data set (linked file) – 2012 period file

• Links birth and death certificate data for all infant deaths.

• Purpose: To use more detailed data from the birth certificate for infant mortality analysis. Linked file provides more accurate data by race and ethnicity than mortality data.

• For this presentation, black and white = non-Hispanic black and non-Hispanic white

2000 2005 2006 2007 2008 2009 2010 2011 2012 20130

1

2

3

4

5

6

7

8

4.62 4.54 4.46 4.42 4.29 4.18 4.05 4.06 4.02 4.04

2.27 2.32 2.22 2.33 2.32 2.21 2.1 2.01 1.96 1.93

Neonatal Postneonatal

Rate

per

1,0

00 li

ve b

irths

6.89

6.07 5.98 5.966.39

6.14

6.68 6.75 6.86 6.61

Infant, neonatal and postneonatal mortality rates, US, 2000 and 2005-2013

Source: 2000-2012 data are from the linked birth/infant death data set. 2013 data are from the main mortality file.

MT

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

VAWV

OH

MI

NY

PA

MD

DE

NJ

CT RI

MA

ME

VT

NH

AK

HI

DC

Decline in infant mortality rates by state, 2005-2013

Source: CDC/NCHS, National Vital Statistics System, main mortality file.

No significant change

Statistically significant decline of <20%

Statistically significant decline of 20% or more

U.S. change = -13.1

MT

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

VAWV

OH

MI

NY

PA

MD

DE

NJ

CT RI

MA

ME

VT

NH

AK

HI

DC

Infant mortality rates by State, 2013

Source: CDC/NCHS, National Vital Statistics System, main mortality file.

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 = 5.96

TOTAL Non-His-

panic black

American Indian or

Alaska na-tive /1

Puerto Rican

Total Hispanic

Non-His-

panic white

Mexican Cuban Central and South American

Asian or Pacific Is-

lander

0

5

10

15

6.86

13.63

8.06 8.30

5.62 5.76 5.53

4.42 4.68 4.89

5.98

11.19

8.40

6.86

5.11 5.04 5.02 5.00

4.14 4.06

2005 2012

Ra

te p

er

1,0

00

live

bir

ths -17%

Infant mortality rates by race and Hispanic origin of mother: US, 2005 and 2012

1/ Includes persons of Hispanic and non-Hispanic origin. Note: Percent change indicates statistically significant change between 2005 and 2012. SOURCE: National Vital Statistics System, NCHS, CDC.

-18%

-13%

-12% -17%

-9% -13%-9%

Infant mortality rates for the five leading causes of infant death by maternal race and Hispanic origin, US, 2012

0

50

100

150

200

250

300

125.7106.6

42.4 38.429.4

116.8

75.1

42.528.7 28.4

148.2

263.2

76.8 80.259

136.6

85.6

24.733.8

15.9

Total White Black Hispanic

Rate

per

100

,000

live

birt

hs

Source: CDC/NCHS linked birth/infant death data set.

TOTAL Non-Hispanic black

Puerto Rican American Indian or

Alaska na-tive*

Mexican Non-Hispanic white

Asian or Pa-cific Islander*

Central and South Amer-

ican

0

50

100

150

200

250

300

350

400

450

500

550

600

650

250.4

626.1

344.2

191.9 182.6 184.5 173.5 159.4

214.1

487.4

287.3

214.8

167.9 158.9 148.1 140.4

2005 2012

Ra

te p

er

10

0,0

00

liv

e b

irth

s

-14%

-22%

-8% -14% -15% -12%

Preterm-related infant mortality rates by race and Hispanic origin of mother: US, 2005 and 2012

*Includes persons of Hispanic and non-Hispanic origin. Rates per 100,000 live births. Source: CDC/NCHS linked birth/infant death data set.

-17%

New variables available from states that have revised their birth certificates

• educational attainment of father• birth interval• receipt of WIC food• exact time of birth• source of payment for the delivery• mother’s body mass index (BMI) (including height and weight)• cigarette smoking before and during pregnancy • infertility treatment• maternal infections• maternal morbidity• 10-minute Apgar score• infant breastfed Available in birth file from 2009 data onwards, and in linked file from 2011 data onwards.

New Data of Variable Quality • 1 study out, 1 underway

Infant mortality rates by source of payment for the delivery and smoking status, 36 states and DC, 2012

Total Medicaid Private insur-ance

Self-pay Other Yes No0

2

4

6

8

10

12

5.99

7.38

4.44

6.916.04

10.3

5.43

Rate

per

1,0

00 li

ve b

irth

s

(uninsured)

Source of Payment for the DeliveryMother smoked during pregnancy

Note: Smoking reported for 35 states and DC. Source: CDC/NCHS: 2012 linked birth/infant death data set.

Infant mortality rates by maternal educational attainment, 36 states and DC, 2012

Total < High school High school diploma

Some college Bachelor's degree

Masters or Doctorate

0

1

2

3

4

5

6

7

8

9

5.98

7.83

7.09

5.59

3.803.33

Rate

per

1,0

00 li

ve b

irth

s

Source: CDC/NCHS: 2012 linked birth, infant death data set.

Infant mortality rates by pre-pregnancy Body Mass Index (BMI), 36 states and DC, 2012

0

1

2

3

4

5

6

7

8

9

10

5.99 5.89

4.81

5.66

6.83

7.76

9.10

Rate

per

1,0

00 li

ve b

irth

s

Underweight = BMI<18.5, normal weight = BMI 18.5-24.9, overweight = BMI 25.0-29.9, obese I = BMI 30.0-34.9, obese II = BMI 35.0-39.9, obese III = BMI 40+. Source: CDC/NCHS: 2012 linked birth/infant death data set.

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).

Percentage of preterm births by maternal race/ethnicity, 2006, 2011, 2012 and 2013

Total Non-Hispanic white Non-Hispanic black Hispanic0

2

4

6

8

10

12

14

16

18

20

12.811.7

18.5

12.211.710.5

16.8

11.711.610.3

16.5

11.611.410.2

16.3

11.3

2006 2011 2012 2013

-11%

-13%

-12%

-7%

Sources: Martin et al. Births: Final Data for 2013.

Infant mortality rates by gestational age, US, 2005 and 2012

Total <32 32-33 34-36 37-38 39-40 41 42+0

20

40

60

80

100

120

140

160

180

200

6.86

183.24

16.697.30 3.08 2.07 2.13 2.665.98

163.14

16.237.1 3.05 1.84 1.87 2.63

2005 2012

Rate

per

1,0

00 li

ve b

irths

-11% -12%

-11%

Source: CDC/NCHS, linked birth/infant death data set.Completed weeks of gestation

-13%

Kitagawa analysis• Used to quantify the relative contribution of changes

in the two components, to the 2005-2012 infant mortality decline.

• Analyzed separately for the total population and for non-Hispanic white, non-Hispanic black, and Hispanic women.

Percent contribution of two components to decline in US infant mortality rate 2005-2012, by race/ethnicity

TOTAL Non-Hispanic white

Non-Hispanic black

Hispanic0%

20%

40%

60%

80%

100%

31

82

44

17

69

18

56

83

Gestational age-specific infant mor-tality rates

Distribution of births by gestational age

Source: CDC/NCHS, linked birth/infant death data set.

Fetal mortality

Fetal mortality rates by race and Hispanic origin of mother, US, 2006-2012

Total Non-Hispanic white

Non-Hispanic black Hispanic0

2

4

6

8

10

12

6.05

4.81

10.73

5.296.05

4.91

10.67

5.33

2006 2012

No statistically significant differences 2006-2012

Source: National vital statistics system, fetal death data set.

Prospective fetal mortality rate by gestational age: US, 2006 and 2012

20 22 24 26 28 30 32 34 36 38 40 420.0

0.2

0.4

0.6

0.8

1.0

1.220062012

Gestational age (weeks)

Rate

per

1,0

00 w

omen

stil

l pre

gnan

t at e

ach

gest

ation

al a

ge

No statistically significant differences at 21-42 weeks of gestation.

Note: The prospective fetal mortality rate is the number of fetal deaths at a given gestational age per 1,000 live births and fetal deaths at that gestational age or greater. Source: CDC/NCHS, fetal death file.

Conclusions • After a plateau from 2000-2005, the US infant mortality rate

declined by 13%, to 5.98 infant deaths per 1,000 live births in 2012, and 5.96 in 2013.

• Infant mortality rates were much higher for women who were:

- Uninsured or on Medicaid- Smokers- High school education or less- Overweight or obese.

• After more than two decades of increase, the percent of preterm births declined by 13% from 2006-2013. Still, preterm birth rates were 60% higher for black than for white women.

• Fetal mortality rates plateaued from 2006-2012.

Conclusions (cont.)• From 2005-2012, the black infant mortality rate fell by 18% from

13.63 to 11.19; however the 2012 black infant mortality rate was still 2.2 times the white rate (5.04).

• Preterm-related infant mortality rates were 3 times higher for black than for white women. Rates for SIDS and unintentional injuries were also higher for black than for white women.

• About 2/3 (69%) of the overall infant mortality decline from 2005-2012 was due to declines gestational age-specific infant mortality rates, and less than 1/3 (31%) was due to declines in preterm births. - However, patterns were very different for white women,

with 82% of their infant mortality decline due to decreases in preterm births.

Contact information

Marian MacDorman 301-458-4356 mfm1@cdc.gov

T.J. Mathews301-458-4363tjm4@cdc.gov