Embed Size (px)
Citation preview
Infant and Maternal Mortality in the US:
Data from the National Vital Statistics System
Marian MacDorman Ph.D., Donna Hoyert Ph.D., and T.J. Mathews M.S.
Division of Vital Statistics
National Center for Health Statistics
Centers for Disease Control and Prevention
Outline
• About the data• Fetal mortality (stillbirth)• Infant mortality
– Trends, selected variables, cause of death– Relationship to preterm birth– Race and ethnic differences– International comparisons
• Maternal mortality
National Vital Statistics System• Based on birth certificates, death certificates, and
reports of fetal death filed in state vital statistics offices, and transmitted to NCHS.
• National data files produced: – Birth (natality) data set– Main mortality file– 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.
– Fetal death data reported by all US states • Most states report fetal deaths of 20 weeks of gestation or more.• Some variability in data completeness and quality.
National Vital Statistics System – Analytical Challenges
• Certificate revision in 2003, but not all states have adopted
• Some items not comparable between old and new versions of the certificates
• Timeliness of data file availability is highly variable– Preliminary birth and death certificate data now available
through 2009– Linked birth/infant death data through 2007– Fetal death data through 2005
• NCHS is working to catch up on data production in a limited resource climate.
Fetal Mortality
All pregnancies, US, 2005(n=6.4 million pregnancies)
Source: Ventura SJ, Abma JC, Mosher WD. Estimated pregnancy rates for the United States, 1990-2005: An Update. National vital statistics reports vol 58 no 4. 2009.
1.2 millioninduced terminations
1.1 millionfetal deaths
4.1 million live births
(28,384)
(25,894)
Fetal mortality rate 1990-2005, and infant mortality rate, 1990-2009
1990
1995
2000
2005
2009
5
6
7
8
9
10
Rat
e pe
r 1,0
00
0
Infant
Fetal
NOTE: Infant mortality rates are the number of infant deaths per 1,000 live births. 2007 data are preliminary. Fetal mortality rates are the number of fetal deaths of 20 weeks of gestation or more per 1,000 live births and fetal deaths. SOURCE: CDC/NCHS, National Vital Statistics System.
Fetal mortality rates by period of gestation: US, 1990-2005
2
3
4
5
1990 1995 2000 2005
Rat
e pe
r 1,0
00 li
ve b
irths
and
feta
l dea
ths
in s
peci
fied
grou
p
28 weeks or more
20-27 weeks
SOURCE: MacDorman MF and Kirmeyer S. Fetal and perinatal mortality, US, 2005. National vital statistics reports vol 57 no 8.
0
Fetal mortality rates by race and Hispanic origin of mother: US, 2005
Total Non-His-panic white
Non-His-panic black
American Indian
Asian or Pacific Is-
lander
Hispanic0
2
4
6
8
10
12
14
3.212.36
6.40
2.83 2.49 2.63
3.03
2.45
4.80
3.352.30 2.82
6.22
4.79
11.13
6.17
4.785.44
Fetal 20-27 weeks Fetal 28 weeks or more
Rate
per
1,0
00 liv
e bi
rths
and
feta
l dea
ths
in s
pecif
ied
grou
p
NOTE: Rates for subtotals do not add exactly to totals due to slight differences in the denominators used for rate computations; see Technical notes.SOURCE: Fetal and perinatal mortality, US, 2005. National vital statistics reports vol 57 no 8.
11.13
Prospective fetal mortality rate by single weeks of gestation: US, 2005
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
20 22 24 26 28 30 32 34 36 38 40 42
Gestational ageNote: 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: MacDorman MF, Kirmeyer S. Fetal and perinatal mortality, US, 2005. National vital statistics reports vol 57 no 8.
43
Infant Mortality:Trends and selected variables
Infant mortality rate, United States, 2000-2009
2000 2001 2002 2003 2004 2005 2006 2007 2008 20090
1
2
3
4
5
6
7
8
6.89 6.84 6.95 6.84 6.78 6.86 6.68 6.75 6.59 6.42
Rat
e pe
r 1,
000
live
birt
hs
Source: 2000-2007 data are from the linked birth/infant death data sets. 2008 and 2009 data are preliminary data from the main mortality files.
Non-Hisp
anic
black
America
n Indian
Puerto R
ican
TOTAL
Non-Hisp
anic
white
Mexica
n
Cuban
Asian or P
acific
Islan
der
Centra
l and South A
merica
n0
2
4
6
8
10
12
14
8.74
4.55 5.14 4.42 3.61 3.68 3.65 3.38 3.14
4.57
4.67 2.572.33
2.02 1.75 1.53 1.4 1.43
Neonatal Postneonatal
Infa
nt
mo
rta
lity
rate
pe
r 1
,00
0 li
ve b
irth
s
13.31
9.22
7.716.75
5.63 5.42 4.78 4.57
5.18
Infant mortality rates by maternal race and ethnicity, 2007
Source: NCHS linked birth/infant death data set, 2007
Non-His-panic black
Puerto Rican
Total Asian or Pacific Is-
lander
Mexican Non-His-panic white
Cuban Central and South
American
0
5
10
15
13.55
7.67.15
6.32 6.115.66
4.79 4.8
9.82
7.73
5.14.25
4.964.14
5.334.52
Born in the U.S. Born elsewhere
Ra
te p
er
1,0
00
liv
e b
irth
s
Infant mortality rates by mother’s place of birth and race/ethnicity, 2007
Source: NCHS, linked birth/infant death data set, 2007
Infant mortality rates by maternal age, US, 2007
Total <15 15-19 20-24 25-29 30-34 35-39 40-44 45+0
5
10
15
20
6.75
14.53
9.73
7.67
5.97 5.376.2
8.35000000000001
11.7
Ra
te p
er
1,0
00
live
birt
hs
Source: NCHS, linked birth/infant death data set, 2007.
Infant mortality rates by plurality, 2007
Total Single Twin Triplet Quadruplet 5+0
50
100
150
200
250
300
350
6.75 5.9328.39
64.69
140.92
296.7
Rat
e p
er 1
,000
liv
e b
irth
s
Source: CDC/NCHS linked birth/infant death data set, 2007
Infant mortality rates by selected variables: 19 states, 2007
<HS HS Some BA/BS college
Nonsmoker Smoker1st After 1st
Source: NCHS, linked birth/infant death data set
Trimester prenatal care began
Maternal Smoking Maternal Education0
5
10
15
5.576.10
7.177.94
10.41
5.79
7.78
3.77
Infa
nt d
eath
s pe
r 1,
000
live
birt
hs
+
Infant mortality rates by leading causes of death, US, 2000 and 2007
Congenital malformations
Short gest/LBW
SIDS Maternal compl.
Unintentional injuries
0
20
40
60
80
100
120
140
160141.8
108.4
62.1
34.321.6
134.9
112.7
57
41.129.7
2000 2007
Ra
te p
er
10
0,0
00
live
birt
hs
Source: NCHS, linked birth/infant death data set.
Percentage of Infant Deaths from Preterm-Related Causes* by Race/Ethnicity, US, 2000 and 2007
Non-His-panic black
Puerto Rican TOTAL Central and South Amer-
ican
Asian or Pacific Is-lander/1
Non-His-panic white
Mexican American Indian or
Alaska na-tive/1
0
5
10
15
20
25
30
35
40
45
5043.7
39.6
34.632.3
30.5 30.8 29.4 27.7
45.0
39.436.0 34.6 35.4
31.6 32.6
24.3
2000 2007
Pe
rce
nt
* Infants born at <37 weeks of gestation with cause of death that was a direct cause or consequence of preterm birth (ICD-10 codes K550, P000, P010, P011, P015, P020, P021, P027, P070-P073, P102, P220-P229, P250-279, P280, P281, P360-P369, P520-P523, P77).1/ Includes persons of Hispanic and non-Hispanic origin.SOURCE: NCHS, linked birth/infant death data set.
Non-His-panic black
American Indian or
Alaska na-tive^
Puerto Rican
Total Non-His-panic white
Mexican Asian or Pacific Is-lander^
Central and South
American
0
5
10
15
13.31
9.22
7.71
6.75
5.63 5.424.78 4.57
5.99
2.253.04
2.431.78 1.77 1.69 1.58
Total Preterm-related
Ra
te p
er
1,0
00
liv
e b
irth
s
Total and preterm-related* infant mortality rates by race and ethnicity of mother, US, 2007
* Preterm-related deaths are those where the infant was born preterm with the underlying cause of death assigned to one of the following ICD-10 categories: K550, P000, P010, P011, P015, P020, P021, P027, P070-P073, P102, P220-P229, P250-279, P280, P281, P360-P369, P520-P523, P77.
^Includes persons of Hispanic and Non-Hispanic origin. SOURCE: NCHS linked birth/infant death data set, 2007
Infant Mortality and Preterm Birth
Infant mortality rates by gestational age ( in weeks), US, 2007
Total <32 32-33 34-36 37-38 39-41 42+ 0
20
40
60
80
100
120
140
160
180
200
6.75
178.36
16.127.42 3.09 2.07 2.62
Ra
te p
er
1,0
00
live
birt
hs
Source: NCHS, linked birth/infant death data set.
Percent of live births and infant deaths by weeks of gestation, US, 2007
<3254%
32-334%
34-3610%
37+32%
Infant Deaths<322% 32-33
2%34-36
9%
37+87%
Births
Source: NCHS, linked birth/infant death data set
Components of preterm birth
“Indicated” preterm birth30-35%
PROM 25-30%
Spontaneous preterm labor40-45%
Source: Goldenberg et al. Lancet, 2008.
Percentage of preterm births: US, selected years
1984
1990
1995
2000
2005
2007
2009
0
2
4
6
8
10
12
14
3.13 3.32 3.31 3.42 3.63 3.66 3.64 3.56 3.51
6.37.3 7.7
8.29.1 9.1 9 8.8 8.7
Per
cent
pre
term
12.7 12.8 12.7 12.3 12.2
10.6 11.0
11.6
9.4
Source: CDC/NCHS national natality files. 1984-2008 are final birth data, 2009 data are preliminary.
34-36 weeks:↑44% 1984-2006↓4% 2006-2009
<34 weeks: ↑ 17% 1984-2006↓ 4% 2006-2009
Percent of preterm births by race and ethnicity, US, 1990 and 2006-2009
Total Non-Hispanic white
Non-Hispanic black
Hispanic0
2
4
6
8
10
12
14
16
18
20
10.6
8.5
18.9
11
12.811.7
18.5
12.212.210.9
17.5
12
1990 2006 2007 2008 2009 1990 2006 2007 2008 2009 1990 2006 2007 2008 2009 1990 2006 2007 2008 2009
Source: CDC/NCHS national natality files. 1990-2008 data are final. 2009 data are preliminary.
Percent of singleton births delivered by cesarean by gestational age, US, selected years
37+ weeks <37 weeks <32 weeks
32-33 weeks
34-36 weeks
0
5
10
15
20
25
30
35
40
45
50
2125
3128
23
29
37
47
42
34
1991199620012006P
erce
nt
Source: MacDorman et al, AJPH, 2010.
Percent of singleton births with induction of labor, US, selected years
37+ weeks <37 weeks <32 weeks
32-33 weeks
34-36 weeks
0
5
10
15
20
25
30
11
85
78
24
16
9
13
171991199620012006P
erce
nt
Source: MacDorman et al, AJPH, 2010.
Percent of singleton preterm (<37 weeks) births by method of delivery, US, 1991-2006
1991
1996
2001
2006
0
2
4
6
8
10
12
Cesarean no induction
Cesarean after induction attempt
Induced vaginal
Spontaneous vaginalP
erc
en
t
Note: Births with method of delivery and induction of labor not stated are excluded. Source: MacDorman et al, AJPH, 2010.
Infant Mortality:Race and ethnic differences
Non-Hisp
anic black
American In
dian
Puerto
Rican
Total
Non-Hisp
anic white
Mexica
nCuba
n
Asian or P
acific Is
lander
Central and
South Americ
an0
2
4
6
8
10
12
14 13.31
9.22
7.716.75
5.63 5.42 5.18 4.78 4.57
Infa
nt
mo
rta
lity
rate
pe
r 1
,00
0 li
ve b
irth
sFigure 1. Infant mortality rates by race and ethnicity of mother, US, 2007
Source: CDC/NCHS linked birth/infant death data set, 2007.
Infant mortality can be partitioned into two key components:
1. Gestational age-specific infant mortality rates (i.e. the mortality rate for infants at a given gestational age).
2. Distribution of births by gestational age.
Gestational age-specific infant mortality rates by race/ethnicity, US, 2007
<32 weeks 32-33 weeks0
50
100
150
200
250
165.6
16.2
209.0
16.9
172.2157.0
28.5
Non-Hispanic white
Non-Hispanic black
Puerto Rican
American Indian
Ra
te p
er
10
00
liv
e b
irth
s
*
Source: CDC/NCHS linked birth/infant death data set, 2007* Figure does not meet standard of reliability or precision: based on <20 deaths in the numerator.
Gestational age-specific infant mortality rates by race/ethnicity, US, 2007
34-36 weeks 37-38 weeks 39-41 weeks0
2
4
6
8
10
12
14
16
7.1
3.02.0
9.4
4.53.4
8.2
3.12.3
14.3
6.1
3.8
Non-Hispanic white
Non-Hispanic black
Puerto Rican
American Indian
Ra
te p
er
10
00
liv
e b
irth
s
Source: CDC/NCHS, linked birth/infant death data set, 2007
Non-H
ispan
ic whit
e
Non-H
ispan
ic blac
k
Puerto
Rican
America
n Ind
ian
0
2
4
6
8
10
12
14
16
18
20
moderately pretermvery preterm
18.3
11.5
14.5 13.9
Percent of preterm births by race and Hispanic origin of mother, United States, 2007
Note: Preterm: <37 weeks of gestation; very preterm: <32 weeks; moderately preterm: 32-36 weeksSource: CDC/NCHS linked birth/infant death data set, 2007
Percent contribution of gestational-age specific infant mortality rates and the distribution of births by gestational
age to race/ethnic differences in infant mortality rates
NHB/NHW infant mortality gap
PR/NHW infant mortality gap
AI/NHW infant mortality gap
0%
20%
40%
60%
80%
100%
78
100
24
22
0
76
Gestational age-specific infant mortality rates
Distribution of births by gesta-tional age
Note: NHW=non-Hispanic white, NHB=non-Hispanic black, PR=Puerto Rican, AI=American IndianSource: NCHS linked birth/infant death data set, 2007
Contribution of causes of death to the non-Hispanic black – non-Hispanic white infant mortality gap, 2007
Preterm
-relat
ed ca
uses
Congenita
l malf
ormati
onsSID
S
Unintentio
nal injurie
s0
100
200
300
400
500
600599
165108
61
178
124
58
30
Non-Hispanic black Non-Hispanic white
Infa
nt m
orta
lity
rate
per
100
,000
live
birt
hs
55% of difference
5% of difference
6% of difference 4% of
difference
Overall, 71% of the black-white infant mortality gap is due to these causes
Source: CDC/NCHS linked birth/infant death data set, 2007
Contribution of causes of death to the Puerto Rican -- non-Hispanic white infant mortality gap, US, 2007
0
50
100
150
200
250
300
350
400
304
137
58
*
178
124
58
30
Puerto Rican Non-Hispanic white
Infa
nt
mo
rta
lity
ra
te p
er
10
0,0
00
liv
e b
irth
s
61% of difference
6% of difference
Source: CDC/NCHS linked birth/infant death data set, 2007. * Figure does not meet standard of reliability or precision – based on <20 deaths in the numerator.
Contribution of causes of death to the American Indian -- non-Hispanic white infant mortality gap, US, 2007
0
50
100
150
200
250
300
350
400
225
184
142
69
178
124
5830
American Indian Non-Hispanic white
Infa
nt
mo
rta
lity
ra
te p
er
10
0,0
00
liv
e b
irth
s
23% of difference
17% of difference
13% of difference
11% of difference
Overall, 64% of the American Indian-white infant mortality gap is due to these causes
Source: CDC/NCHS linked birth/infant death data set, 2007.
Infant Mortality:International comparisons
Infant mortality rates, selected countries, 2005
SlovakiaUnited States
PolandNorthern Ireland
Cuba HungaryCanada
ScotlandNew Zealand
AustraliaEngland and Wales
NetherlandsItaly
IsraelDenmark
AustriaSwitzerland
SpainIreland
GermanyGreece
BelgiumFrance
PortugalCzech Republic
NorwayFinland
JapanHong Kong
SwedenSingapore
0 1 2 3 4 5 6 7
7.26.9
6.46.3
6.26.2
5.45.2
5.15.05.0
4.94.7
4.64.4
4.24.2
4.14.0
3.93.8
3.73.6
3.53.4
3.13.0
2.82.42.4
2.1
Rate per 1,000 live birthsSource: Health, United States, 2008
Infant mortality rates excluding births at <22 weeks of gestation, US and selected European countries, 2004
SlovakiaPoland
HungaryUnited States
ScotlandEngland and Wales
NetherlandsIreland
DenmarkGermany
AustriaSpain
Northern IrelandItaly
GreecePortugal
FranceCzech Republic
FinlandSwedenNorway
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
7.0
6.8
6.6
5.8
4.9
4.9
4.6
4.6
4.4
4.1
4.1
4.0
4.0
4.0
4.0
3.9
3.9
3.7
3.4
3.0
3.0
Rate per 1,000 live births
Source: NCHS linked birth/infant death data set (for US data), and European Perinatal Health Report (for European data).
Percentage of preterm births, United States and selected European countries, 2004
United StatesAustria
GermanyHungary
SpainScotland
England and WalesNetherlands
NorwayCzech Republic
DenmarkItaly
PolandPortugal
Northern IrelandFrance
SlovakiaSwedenGreeceFinlandIreland
0 2 4 6 8 10 12 14
12.411.4
8.98.6
8.07.67.57.4
7.17.06.96.86.86.8
6.66.36.36.3
6.05.65.5
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).
Infant mortality rate for the US and Sweden, and the US infant mortality rate standardized for
Sweden’s gestational age distribution, 2004
0
2
4
6
3.0
5.83.9
Infa
nt m
ort
alit
y r
ate
33% lower
Note: Excludes births at <22 weeks of gestation. Source: NCHS linked birth/infant death data set (for US data), and European Perinatal Health Report (for Swedish data).
Discussion – International Rankings• Although there are reporting differences between countries,
they are not the primary explanation for the United States’ relatively low international ranking.
• In 2005, 22 countries had infant mortality rates ≤5.0.
• One would have to assume that these countries did not report more than 1/3 of their infant deaths for their infant mortality rates to equal or exceed the US rate.
• This level of underreporting appears unlikely for most developed countries.
• The main cause of the US’ high infant mortality rate when compared to Europe is the very high percentage of preterm births in the US, the period when infant mortality is greatest.
Maternal Mortality:What’s the real story?
Definitions
Maternal death: Death of a woman while pregnant or within 42 days of the end of pregnancy from any cause related to or aggravated by the pregnancy.
Late maternal death: Death of a woman from direct or indirect obstetric causes more than 42 days but less than one year after the end of the pregnancy.
Maternal mortality rate: Number of maternal deaths x 100,000(also known as maternal mortality ratio) Number of live births
Source: World Health Organization, International Classification of Diseases, 10th Revision.
Two Main Maternal Mortality Data Systems
National Vital Statistics System (NVSS):• Official maternal mortality rate for US• Based upon death certificates• Maternal deaths, late maternal deaths, sequelae of maternal death• Coded according to WHO rules
Pregnancy Mortality Surveillance System (PMSS):• Complementary activity to NVSS• Based upon death certificates, matched records, media reports, maternal mortality review committee reports etc.• Pregnancy-related deaths, pregnancy associated deaths• Reviewed and coded according to system developed by ACOG/CDC Maternal Mortality Study Group
Maternal mortality rates from the National Vital Statistics System and the Pregnancy Mortality Surveillance System, US, 1980-2002
1980 1985 1990 1995 2000 20050
2
4
6
8
10
12
14
16
18
Rate
per
100
,000
live
bir
ths
PMSS
NVSS
Source: CDC/NCHS National Vital Statistics System, and CDC Pregnancy Mortality Surveillance System.
Recent change involving separate question
• Beginning with data for 2003, states have been adopting a separate question on their death certificates on whether a woman was pregnant at the time of death or within 42 days of death.
• Information from the question is used to supplement what is reported on the cause-of-death statement to improve ascertainment of maternal deaths
•The new question increases ascertainment of maternal deaths leading to higher maternal mortality rates.
Number of states with pregnancy question on the death certificate, 2003-2011
2003 2004 2005 2006 2007 2008 2009 2010 20110
5
10
15
20
25
30
35
40
45
50 412
1822 24
31 3135 38
Standard questionAnother questionNo question
Source: CDC/NCHS National Vital Statistics System.
Maternal mortality rates from the National Vital Statistics System and the Pregnancy Mortality Surveillance System, US, 1980-2007
1980 1985 1990 1995 2000 2005 20070
2
4
6
8
10
12
14
16
18
Rate
per
100
,000
live
bir
ths PMSS
NVSS
Source: CDC/NCHS National Vital Statistics System, and CDC Pregnancy Mortality Surveillance System.
Maternal Mortality is Still a Major Public Health Problem
• Maternal mortality rates in the US are high compared to other industrialized countries.
• No improvement in maternal mortality rates in the US since the 1980’s
• 500-600 maternal deaths each year in the United States
• Unexpected deaths of young women many in their 20s and 30s, many with families and other children
• There are large race and ethnic disparities in maternal mortality – some of the widest disparities found in public health.
• At least 40% of pregnancy-related deaths are preventable (Berg, 2005). Many due to common problems such as hemorrhage or complications of maternal chronic diseases (i.e. diabetes, hypertension).
Maternal mortality rates, selected industrialized countries, 2003-2004 data
United States
Denmark
Netherlands
England and Wales
France
Canada
Germany
0 2 4 6 8 10 12 14
12.6
9.3
8.8
7.2
7
6.2
5.4
Source: European data from the European Perinatal Health Report; Canadian data from Statistics Canada, Canadian vital statistics, death database; US data from the National Vital Statistics System.
Maternal mortality rates by race and Hispanic origin, US, 2007
Series10
5
10
15
20
25
30
35
Total Hispanic Non-Hispanic white
Non-Hispanic black
Rat
e p
er 1
00,0
00 l
ive
bir
ths
12.7
8.910.5
28.4
Source: CDC/NCHS, National Vital Statistics System, Mortality
Maternal mortality rates by age, US, 2007
Under 20 20-24 25-29 30-34 35 and over0
5
10
15
20
25
30
35
7.1 8.1 9.412.1
32.3
Age in years
Rat
e pe
r 10
0,00
0 liv
e bi
rths
Source: CDC/NCHS National Vital Statistics System, Mortality
Summary
• Stagnation in the rate of decline of both infant (2000-2007) and fetal (2003-2005) mortality rates
• No detectible decline in maternal mortality rate since 1982
• Recent modest decline in preterm birth (2006-9) and infant mortality (2007-9)
• Still, preterm birth rates and infant mortality rates are much higher in the US than in most developed countries.
Summary (cont.)
• Large race and ethnic disparities in fetal, infant and maternal mortality suggest that not all race/ethnic groups have benefited equally from social and medical advances.
• Preterm birth is a primary cause of high infant mortality in the US, and contributes substantially to both race and ethnic disparities and the US’ poor international ranking.
• Interventions to address the nation’s high preterm birth rate must address prevention of both spontaneous preterm labor and iatrogenic preterm birth.
Questions?
Marian MacDorman, Ph.D.Statistician, Division of Vital StatisticsNational Center for Health Statistics(301) [email protected]
2007 linked file report available at : http://www.cdc.gov/nchs/data/nvsr/nvsr59/nvsr59_06.pdfSome copies in the back of the room.
