Current trends and issues in
British fertility analysis
Jessica Chamberlain
Fertility Analysis Unit, Office for National Statistics
Thanks to Steve Smallwood, John Jeffs and Baljit Gill
Overview
1) Current trends in fertility
• Background
• Analysis of increases - Age
- Geography
- Registration type
- Country of birth
- Parity
2) Current issues in fertility
• Fertility and migration
• Subnational fertility
Trends in the TFR
Total fertility rate, England and Wales 1938-2004
Children per woman
3.5
1960s baby
boom
3
Post World War
Two baby boom
2.5
Recent
rise in
fertility
2
1.5
1930s low
fertility
Late 1970s low
fertility
1
0.5
0
1938
1943
1948
1953
1958
1963
1968
1973
1978
1983
1988
1993
1998
2003
Trends in childbearing behaviour
• Decline in completed family size. Decrease from
2.46 children for 1934 cohort to 1.99 for most
recent cohort to complete childbearing.
• Increase in proportion of women remaining
childless. Increase from 9 per cent of women born
in 1945 to around 20 per cent for women soon to
complete childbearing.
• Increased mean age at first birth
• Childbearing to women in their 20s has decreased
and increased to women in their 30s.
Recent increase in fertility
• Record low TFR of 1.63 in 2001.
• Increase every year since then.
• The rise from 2002 to 2003 was the largest absolute and
proportional change in TFR since 1979.
Year
TFR
2001
2002
2003
2004
1.63
1.65
1.73
1.78
Absolute
change
0.02
0.08
0.06
Percentage
change
1.1
4.6
3.2
Has this increase occurred all over the
UK?
Scotland
Year
TFR
2001
2002
2003
2004
1.49
1.48
1.54
1.60
Northern Ireland
Year
TFR
2001
2002
2003
2004
1.80
1.77
1.81
1.88
Absolute
change
-0.01
0.06
0.06
Absolute
change
-0.03
0.04
0.07
Percentage
change
-0.4
3.6
3.9
Percentage
change
-1.6
2.3
3.5
Has this increase occurred all over
England and Wales?
• This rise has occurred all over England and Wales to varying
degrees.
• In 2003 all GORs except the North East saw rises of 4.3 to
4.8 per cent in their TFR from 2002. In 2004 the TFR
increased by 3 or more per cent everywhere except the
South East.
NORTH EAST
NORTH WEST
YORKSHIRE AND THE HUMBER
EAST MIDLANDS
WEST MIDLANDS
EAST OF ENGLAND
LONDON
SOUTH EAST
SOUTH WEST
WALES
2001
1.56
1.66
1.66
1.61
1.74
1.67
1.61
1.62
1.58
1.66
TFR
2002
1.60
1.66
1.67
1.63
1.75
1.69
1.63
1.63
1.62
1.63
2003
1.66
1.73
1.76
1.70
1.84
1.77
1.71
1.71
1.70
1.71
2004
1.71
1.81
1.82
1.76
1.91
1.83
1.76
1.77
1.74
1.77
Does the increase apply across women of
all ages?
Age-specific fertility rates, England and Wales, 1980-2004
Births per 1,000 women
140
120
25-29
100
30-34
80
20-24
60
35-39
40
15-19
20
40-44
0
1984
1986
1988
1990
1992
1994
Year
1996
1998
2000
2002
2004
Registration type
• Percentage increase in births jointly registered both
at same address and at different addresses was
greater than the overall percentage increase in
births.
• Percentage increase in births registered by the
mother alone was below the overall percentage
increase in the number of births.
Percentage change in number of births from previous year, by registration type
All births
2002
2003
2004
0.2
4.1
2.9
Married
-0.7
2.8
1.6
Unmarried
1.6
5.9
4.6
Jointly registered
Same
Different
address address
2.4
2.0
5.7
8.5
4.7
7.3
Sole
registration
-1.4
3.9
1.1
Country of birth of parents
• Since 1995 the proportion of births occurring to
mother’s born outside the UK has been rising.
• This rise became steeper between 1999 to 2004.
• In 2004 19.5 per cent of all births were to women
born outside of the UK.
Percentage change in number of births on previous year
Country of birth of mother
Total
United Kingdom
Total outside UK
2002
2003
2004
0.2
-1.2
7.1
4.1
3.0
8.7
2.9
1.8
7.4
Parity
• Increases in probability of progression to first birth,
particularly for older women in last two years.
• So the number of women who would remain
childless has decreased from one in four women to
one in five.
• Probability of having a second birth has not
increased back to previous levels, but the number
of women exposed to having a second birth has
increased.
• Some of low fertility from 1995 onwards appears to
be associated with a decline in women in their 30s
progressing to have a second birth.
Period Parity Progression ratios
Year
1980
1990
2000
2001
2002
2003
2004
0-1
0.835
0.795
0.762
0.757
0.762
0.780
0.792
1-2
0.795
0.810
0.764
0.757
0.755
0.764
0.769
2-3
0.399
0.422
0.380
0.375
0.376
0.394
0.407
3-4
0.342
0.357
0.335
0.332
0.338
0.352
0.367
Percentage changes on previous year's PPPR
Year
0-1
1-2
2-3
3-4
2000
-1.3%
-1.7%
-2.9%
0.8%
2001
-0.6%
-0.9%
-1.2%
-0.8%
2002
0.6%
-0.3%
0.3%
1.9%
2003
2.4%
1.2%
4.8%
4.0%
2004
1.6%
0.7%
3.3%
4.3%
4-5+
0.362
0.429
0.404
0.407
0.413
0.426
0.435
4-5+
3.5%
0.6%
1.4%
3.2%
2.3%
Occurrence-exposure rates- 1st births
First births per 1,000 childless women
140
120
1980
1990
2000
2004
100
80
60
40
20
0
14
16
18
20
22
24
26
28
30
Age
32
34
36
38
40
42
44
Occurrence-exposure rates - 2nd births
Second births per 1,000 women with one child
300
250
1980
1990
2000
2004
200
150
100
50
0
14
16
18
20
22
24
26
28
30
Age
32
34
36
38
40
42
44
Occurrence-exposure rates - 2nd births
Second births, per 1,000 women with one child
250
200
Age 30
150
100
Age 35
50
1965
1970
1975
1980
1985
1990
1995
2000
Is this rise the start of a new trend?
• Fertility can vary year to year due in part to change in
•
•
•
•
timing of births.
There were substantial rises in fertility in 1978 and
1979 after a period of record low fertility had occurred,
however fertility fell again in the early 1980s.
2000 to 2002 were years of particularly low fertility, so
may be some short term catching up of births.
The rise in births to women in their 30s may indicate
the continued long term trend of postponement of
births to older ages.
May, in part, be an effect of the timing of births of
migrants.
Future Projects
• Two future projects that the Fertility Analysis Unit at
ONS are undertaking to further understanding of
fertility within England and Wales:
1) Relationship between migration and fertility
2) Calculating and analysing subnational fertility
Births to non-UK born mothers
Percentage of births to mothers born outside the United Kingdom,
England and Wales 1969 - 2004
Percentage
20
15
10
5
0
1969
1974
1979
1984
1989
1994
1999
2004
Gross female international migration
Gross inflow of female international migrants by age, England and
Wales 1993-2003
Thousands
250
200
150
100
50
0
1993
1994
1995
1996
Under 15
1997
1998
15-44
1999
45-64
2000
2001
2002
2003
65 and over
Source: MN, Table 2.9
1) Fertility and migration
• Disruption hypothesis
• When standardised for age women have lower
fertility before migration than women in the
destination country.
• Then migrants show a rise and peak in fertility after
migration.
• After period of time fertility of immigrants declines
and may become similar to the fertility of native
born women.
• Migration and family building in many cases are
interrelated processes.
Fertility of immigrant women by age at
entry into France, 1991-1998
Source: Toulemon (2004)
Literature
• This relationship has been shown in studies in
America, Canada, France, Sweden and Norway.
• Age at entry and country of origin affect fertility
pattern before and after migration
• Different types of migration to consider: economic
migration and migration to join family. Also
refugees and asylum seekers likely to have a
different pattern.
• Toulemon (France) - Need to calculate the TFR for
overseas born women taking into account age at
entry and duration of stay so as not to overestimate
fertility.
Using the General Household Survey
(GHS) for England and Wales
• GHS contains: age, country of birth, year of entry to
•
•
•
•
UK and fertility history for 1971-1996, 1998 and
2000-2004 surveys.
Numbers available in GHS large enough - 615
women born outside of the UK in 2002 GHS.
May need to combine several year’s of GHS data.
Also have fertility intentions data.
Other possible data sources? BHPS?
2) Subnational fertility - Issues
• Method of standardisation
• Confidence intervals on fertility rates
• Confidence intervals on population, from census
• Other geographies, e.g. rural/urban, primary care
organisations
• Time trends and changing boundaries
• Correlations with other factors e.g. level of
deprivation, employment of women
Highest and lowest LA Total Fertility Rates,
England and Wales 2003
Local Authority
TFR
Lowest 10 TFRs
City of London LB
Cambridge CD
Westminster, City of LB
Exeter CD
Kensington and Chelsea LB
Durham CD
Oxford CD
Norwich CD
York UA
Camden LB
0.82
1.12
1.22
1.27
1.29
1.29
1.34
1.35
1.37
1.38
Highest 10 TFRs
Newham LB
Blackburn with Darwen UA
Bradford MCD
Luton UA
Hackney LB
Oldham MCD
Hyndburn CD
Walsall MCD
Mid Devon CD
Slough UA
2.34
2.27
2.23
2.23
2.19
2.19
2.19
2.11
2.11
2.05
95% Confidence Interval
Lower limit Upper limit
0.61
1.03
1.05
1.19
1.18
1.27
1.2
1.35
1.24
1.35
1.19
1.38
1.27
1.40
1.28
1.42
1.31
1.43
1.33
1.43
2.27
2.17
2.17
2.16
2.12
2.11
2.06
2.04
1.96
1.95
2.40
2.36
2.28
2.31
2.25
2.27
2.31
2.19
2.26
2.14
Source: http://www.nchod.nhs.uk - TFRs with confidence intervals for 2003 for LAs,
PCOs and other geographies.
Any questions or suggestions?