NCHS Data Brief ■ No. 21 ■ August 2009

Delayed Childbearing: More Women Are Having Their

First Child Later in Life

T.J. Mathews, M.S., and Brady E. Hamilton, Ph.D.

u.s. department of health and human services

Centers for Disease Control and Prevention

National Center for Health Statistics

Key findings

Data from the Birth Data 

File, National Vital Statistics 

System

• The average age of firsttime mothers increased 3.6 

years from 1970 to 2006, from 

21.4 to 25.0 years.

• Increases in average 

age at first birth were more 

pronounced in the 1970s and 

1980s.

• Average age at first birth 

increased in all states and 

the District of Columbia; the 

District of Columbia (5.5 

years) and Massachusetts (5.2 

years) had the largest increases 

since 1970.

• In 2006, Asian or Pacific 

Islander women had the oldest 

average age at first birth (28.5 

years) and American Indian or 

Alaska Native women had the 

youngest (21.9 years). 

• The average age at first 

birth has been increasing in 

many developed nations.

Of particular interest to both researchers and the public is the “average” age 

of women when they have a child, especially their first. Age at first birth 

influences the total number of births that a woman might have in her life, 

which impacts the size, composition, and future growth of the population. 

The age of the mother, both younger and older, plays a strong role in a wide 

range of birth outcomes (e.g., birthweight, multiple births, and birth defects), 

so it is critical to track the average age at which women have their first birth. 

Keywords: average age • first birth • race and Hispanic origin • state-specific 

average age

Are first-time mothers older?

The average age of first-time mothers increased by 3.6 years, from 21.4 years 

in 1970 to 25.0 years in 2006. While the average age for first births increased 

from 1970 to 2006, the increases were more dramatic during the first two 

decades (1970 to 1990) (Figure 1).

Figure 1. Average age of mother at first birth: United States, 1970–2006 Age of mother in years

25.0

Year

SOURCE: CDC/NCHS, National Vital Statistics System.

 0

22

24

26

23

2006

1970 1975 1980 1985 1990 1995 2000 2005

21.4

25
NCHS Data Brief ■ No. 21 ■ August 2009

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From 1970 to 2006 the proportion of first births to women aged 35 years and over increased 

nearly eight times (1,2). In 2006, about 1 out of 12 first births were to women aged 35 years and 

over compared with 1 out of 100 in 1970. According to preliminary data, the proportion for 2007 

was the same as in 2006 (3). In 2006, only 21% of first births were to mothers under age 20, 

down from 36% in 1970 (Figure 2).

Figure 2. Percentage of first births, by age of mother: United States, 1970–2006

SOURCE: CDC/NCHS, National Vital Statistics System. Percent

Year

0

20

40

60

80

100

35 years and over

20–34 years

Under 20 years

2006

1970 1975 1980 1985 1990 1995 2000 2005

Does average age of mother at first birth differ by geographic area over 

time?

The average age of first-time mothers increased for all states and the District of Columbia 

between 1970 and 2006. The increases ranged from 2.0 years for women in New Mexico to over 

5.0 years for women in the District of Columbia, New Hampshire, and Massachusetts (Figure 3). 

Figure 3. Absolute increase in mother’s average age at first birth, by state: United States, 1970–2006

SOURCE: CDC/NCHS, National Vital Statistics System.

MT

WY

ID

WA

OR

NV

UT C A

AZ

ND

S D

NE

C O

NM

TX

OK

KS

AR

LA

MO

IA

MN

W I

IL IN

KY

TN

MS AL GA

FL

S C

NC

WV VA

OH

MI

NY

P A

MD

DE

DC

NJ

CT R I

MA

ME

VT

NH

AK

HI

4.3–5.5 years 

3.8–4.2 years 

3.3–3.7 years 

3.0–3.2 years 

2.0–2.9 years 

United States: 3.6 years
NCHS Data Brief ■ No. 21 ■ August 2009

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There are significant differences in average age at first birth among the states. In 1970, the 

average age at first birth was lowest in Arkansas (20.2 years) and highest in Connecticut, 

Massachusetts, and New York (22.5 years). In 2006, Massachusetts had the highest average age at 

first birth (27.7 years) and Mississippi had the lowest (22.6 years) (Table 1). 

Table 1. Average age of mother at first birth, by state (1970 and 2006) and absolute change (1970–2006): 

United States and each state

[By place of residence]

State 1970 2006 Absolute change, 

1970–2006

United States 21.4 25.0 3.6

Alabama 20.5 23.6 3.1

Alaska 21.6 24.3 2.7

Arizona 21.2 24.0 2.8

Arkansas 20.2 23.0 2.8

California 21.8 25.6 3.8

Colorado 21.6 25.7 4.1

Connecticut 22.5 27.2 4.7

Delaware 21.4 25.0 3.6

District of Columbia 21.0 26.5 5.5

Florida 21.0 25.0 4.0

Georgia 20.7 24.5 3.8

Hawaii 22.4 25.7 3.3

Idaho 20.8 23.8 3.0

Illinois 21.5 25.4 3.9

Indiana 20.9 24.0 3.1

Iowa 21.3 24.5 3.2

Kansas 21.1 24.2 3.1

Kentucky 20.7 23.8 3.1

Louisiana 20.5 23.3 2.8

Maine 21.2 25.6 4.4

Maryland 21.6 26.1 4.5

Massachusetts 22.5 27.7 5.2

Michigan 21.2 25.0 3.8

Minnesota 22.0 25.8 3.8

Mississippi 20.3 22.6 2.3

Missouri 21.1 24.1 3.0

Montana 21.2 24.5 3.3

Nebraska 21.4 24.7 3.3

Nevada 21.3 24.6 3.3

New Hampshire 21.6 26.7 5.1

New Jersey 22.4 27.2 4.8

New Mexico 21.0 23.0 2.0

New York 22.5 26.8 4.3

North Carolina 20.8 24.6 3.8

North Dakota 21.5 24.7 3.2

See note at end of table.
NCHS Data Brief ■ No. 21 ■ August 2009

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Table 1. Average age of mother at first birth, by state (1970 and 2006) and absolute change (1970–2006): 

United States and each state—Con.

[By place of residence]

State 1970 2006 Absolute change, 

1970–2006

Ohio 21.3 24.7 3.4

Oklahoma 20.7 23.1 2.4

Oregon 21.4 25.4 4.0

Pennsylvania 21.7 25.5 3.8

Rhode Island 22.1 26.2 4.1

South Carolina 20.6 24.0 3.4

South Dakota 21.1 24.0 2.9

Tennessee 20.7 24.0 3.3

Texas 20.9 23.9 3.0

Utah 21.4 23.9 2.5

Vermont 21.7 26.5 4.8

Virginia 21.4 25.8 4.4

Washington 21.5 25.9 4.4

West Virginia 20.8 23.9 3.1

Wisconsin 21.8 25.3 3.5

Wyoming 21.0 23.7 2.7

NOTE: Difference of averages was significant at p<0.05 for the United States and each state.

Does the average age of first-time mothers differ by race and Hispanic 

origin?

The average age at first birth increased for all racial and ethnic groups between 1990 and 2006 

with increases ranging from 0.6 years for American Indian or Alaska Native (AIAN) women to 

1.7 years for Asian or Pacific Islander (API) women.

In 2006, API women had the oldest average age at first birth (28.5 years), whereas AIAN women 

had the youngest (21.9 years); a difference of 6.6 years. The average age at first birth for

non-Hispanic white women (26.0 years) was older than the average for the U.S. population (25.0 

years) while those for non-Hispanic black (22.7 years) and Hispanic women (23.1 years) were 

younger (Figure 4).
NCHS Data Brief ■ No. 21 ■ August 2009

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Figure 4. Average age of mother at first birth, by race and Hispanic origin of mother: United States, 1990 and 2006

1

For 1990, excludes data for New Hampshire and Oklahoma, which did not report Hispanic origin.

SOURCE: CDC/NCHS, National Vital Statistics System.

Race and Hispanic origin

28.5

26.8

26.0

25.0 25.0

24.2

23.1

22.4 22.7

21.7 21.9

21.3

 0

15

20

25

30 1990 2006

American Indian

 or Alaska Native

Non-Hispanic

 black1

Hispanic1 Non-Hispanic Total

 white1

Asian or

 Pacific Islander

Age of mother in years

Variations among race and Hispanic origin groups within states tend to mirror these patterns with 

API women being the oldest first-time mothers, and AIAN women the youngest (access Table 2

online).

How does the United States compare with other countries in average age at 

first birth?

According to the latest data for selected countries, the average age at first birth in 2006 ranged 

from 25.0 years in the United States to 29.4 years in Switzerland. The average age at first birth 

has steadily increased among developed nations (1,4–6). All of the countries shown here had 

increases in average age at first birth since 1970, with a range of 2.9 years in Sweden to 4.6 years 

in Denmark. While the United States was in the middle of this range with a 3.6-year increase 

between 1970 (21.4 years) and 2006 (25.0 years), it had the youngest average age at first birth in 

both time periods for the nations shown (Figure 5).
NCHS Data Brief ■ No. 21 ■ August 2009

■  6  ■

0 20 25 30

2006

1970

Switzerland

Japan

Netherlands

Sweden

Italy1

Ireland

Greece

Denmark

Finland

Canada

France

Hungary

Poland

United States

Figure 5. Average age of mother at first birth: Selected countries, 1970 and 2006

1

Latest data are for 2005.

SOURCES: CDC/NCHS, National Vital Statistics System, Council of Europe, Vienna Institute of Demography, Statistics Canada, and Japanese Ministry of Health,

Labour and Welfare.

Age of mother in years

21.4

22.8

23.7

23.8

25.9

27.8

28.0

25.0

22.8

24.4

24.4

25.0

26.9

28.0

28.4

25.3

25.9

25.6

28.7

29.0

25.0

24.8

25.3

28.7

28.8

29.2

29.4

28.5

Summary

Delayed childbearing in the United States is evident in the 3.6-year increase in the average age at 

first birth between 1970 and 2006 (2,7–9). The dramatic increase in women having their first birth 

at the age of 35 years and over has played the largest role in the increased average age of firsttime mothers.

Since 1970, the average age at first birth has increased in all states, rising 5.0 years or more in the 

District of Columbia, Massachusetts, and New Hampshire, while increasing less than one-half 

that number in Mississippi, New Mexico, and Oklahoma.

Since 1990, there have been increases in average age at first birth for all racial and Hispanic 

origin groups but there remain large differences by race and ethnicity. In 1990 and 2006, AIAN 

women had the youngest average age at first birth; the average age at first birth was oldest for API 

women, followed by non-Hispanic white women.
NCHS Data Brief ■ No. 21 ■ August 2009

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Along with the United States, many other developed nations have observed increases in average 

age at first birth with some now averaging near 30.0 years of age. Increase in age at first birth, 

which affects the number of children a woman will have during her childbearing years, has 

important ramifications for family size and overall population change. 

Definitions

Average age: The arithmetic mean of mother’s age at birth.

First birth: The first child born alive to a woman. 

Race and Hispanic origin: Race and Hispanic origin are reported separately on birth certificates. 

Persons of Hispanic origin may be of any race. Persons of non-Hispanic ancestry are further 

classified by race because there are substantial differences in fertility and maternal characteristics 

between Hispanic and non-Hispanic persons. Persons of AIAN and API ancestry are not classified 

separately by Hispanic origin because the majority of these persons are non-Hispanic. Multiplerace data reported since 2003 were bridged to single-race categories for comparability among 

states and for trend analysis (1).

Data sources and methods

This report contains data from the birth data set, which is part of the National Vital Statistics 

System (NVSS). NVSS contains all live births reported in the United States. The birth data set is 

the primary data set for analyzing birth trends and patterns in the United States. Birth data sets are 

available from NCHS at http://www.cdc.gov/nchs/data_access/VitalStatsOnline.htm and 

http://www.cdc.gov/nchs/VitalStats.htm.

About the authors

T.J. Mathews and Brady E. Hamilton are with the Centers for Disease Control and Prevention’s 

National Center for Health Statistics, Division of Vital Statistics, Reproductive Statistics Branch.

References

1. Martin JA, Hamilton BE, Sutton PD, et al. Births: Final data for 2006. National vital statistics 

reports; vol 57 no 7. Hyattsville, MD: National Center for Health Statistics. 2009. 

2. Mathews TJ, Hamilton BE. Mean age of mother, 1970–2000. National vital statistics reports; 

vol 51 no 1. Hyattsville, MD: National Center for Health Statistics. 2002. 

3. Hamilton BE, Martin JA, Ventura SJ. Births: Preliminary data for 2007. National vital 

statistics reports, Web release; vol 57 no 12. Hyattsville, MD: National Center for Health 

Statistics. Released March 18, 2009.

4. Vienna Institute of Demography. European demographic data sheet 2008. Available from: 

http://www.oeaw.ac.at/vid/datasheet/download/sources_notes_datasheet2008.pdf. [Accessed 

5/29/09].
NCHS Data Brief ■ No. 21 ■ August 2009

5. Council of Europe Publishing. Recent demographic developments 

in Europe, 2002. Available from: http://www.coe.int/t/e/social_cohesion/

population/d%C3%A9mo211960EN.PDF. [Accessed 5/29/09].

6. Statistics Canada. Report on the demographic situation in Canada, 2005 

and 2006. Available from: http://dsp-psd.pwgsc.gc.ca/collection_2008/

statcan/91-209-X/91-209-XIE2004000.pdf. [Accessed 5/29/09].

7. Gregory E. Ready: Why women are embracing the new later 

motherhood. Basic Books. 2007.

8. Chandra A, Martinez GM, Mosher WD, et al. Fertility, family planning, 

and reproductive health of U.S. women: Data from the 2002 National 

Survey of Family Growth. National Center for Health Statistics. Vital Health 

Stat 23(25). 2005.

9. Ventura SJ. Trends and variations in first births to older women 1970–

86. National Center for Health Statistics. Vital Health Stat 21(47). 1989.

Suggested citation

Mathews TJ, Hamilton BE. Delayed 

childbearing: More women are having their 

first child later in life. NCHS data brief, no 

21. Hyattsville, MD: National Center for 

Health Statistics. 2009.

Copyright information

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or copied without permission; citation as to 

source, however, is appreciated.

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