Childbearing for women born in different years, England and Wales: 2020

• Women in England and Wales born in 1975 who completed their childbearing years in 2020, had on average 1.92 children, no change from those born in 1974 but a lower average compared with the 2.08 for their mothers' generation (assumed to be born in 1949).

• Two child families remain the most common family size (37%), however this is a decrease in the proportion of those having two children compared with their mothers' generation born in 1949 (44%).

• Of women aged 45 years and born in 1975 who had completed their childbearing years in 2020, 18% were childless, with 17% having only one child, both of which are increases compared with their mothers' generation (both 13%).

• The most common age for women born in 1975 to give birth  was 31 years, an increase compared with 22 years for their mothers' generation born in 1949.

• Half of women (50%) born in 1990 (the most recent cohort to reach age 30 years) remained childless by their 30th birthday; this is the first cohort where half remain childless by 30 years of age.

Statistician’s comment

“We continue to see a delay in childbearing, with women born in 1990 becoming the first cohort where half of the women remain childless by their 30th birthday. Levels of childlessness by age 30 have been steadily rising since a low of 18% for women born in 1941. Lower levels of fertility in those currently in their 20s indicate that this trend is likely to continue.

The average number of children born to a woman has been below two for women born since the late 1950’s. While two child families are still the most common, women who have recently completed their childbearing are more likely than their mothers’ generation to have only one child or none at all.”

Amanda Sharfman, Centre for Ageing and Demography, Office for National Statistics

Follow Centre for Ageing and Demography on Twitter @RichPereira_ONS

Most common age at childbirth

The standardised mean age of a mother has been increasing since the mid 1970's and reached a record high of 30.7 years in 2019 and 2020.

The most common age at childbirth for women born in 1975 who reached 45 years and are assumed to have completed their childbearing years in 2020 was 31 years. This is an increase in age, compared with 22 years for their mothers' generation born in 1949 (based on the standardised mean age of a mother in 1975 of 26.4 years). Interestingly, the most common age of childbirth for their grandmothers' generation, born in 1921 (standardised mean age of mother in 1949 of 28.3 years), was higher than the subsequent generation at 26 years, possibly because of World War Two. 

Family size

Women born in 1975, who are assumed to have completed their childbearing years in 2020, had on average 1.92 children, the same as those born in 1974 (Figure 1). A low of 1.89 was seen for women born in 1972 and 1973. In the short term, the average number of children is likely to remain at or above 1.92 based on current levels of cumulative fertility for subsequent cohorts (women born in the mid-to-late 70's).

In comparison, women born in 1949, who are assumed to be the generation of mothers of the women born in 1975, had a larger average completed family size of 2.08 children. For women born since the later 1950's, the average number of children born to them has been below 2.0.

While average family size has decreased, two children families remain the most common family size across both generations, with 37% of women born in 1975 and 44% of those born in 1949 having two children. For those born in 1975, 27% had three or more children and 17% had only one child, compared with 30% and 13% respectively, for their mothers' generation.

The average number of live-born children that women have by their 30th birthday gives an indication of trends in family size for cohorts of women born more recently. Although, as women delay childbearing to older ages, this will be less indicative of trends in completed family size.

There was a year-on-year decline in the average number of children women have by age 30 years from a peak of 1.89 children per woman born in 1941, through to 1978 (0.98 children). There was then a slight uptick between 1979 and 1987. However, since the cohort of women born in 1988 have reached 30 years, there has been a decrease again, resulting in an all-time low of 0.96 children for the 1990 cohort (latest cohort reaching 30 years).

Childlessness

The proportion of women who reached 30 years without a child has changed substantially over time (Figure 2), with half (50.1%) of the latest cohort to reach 30-years-old (born in 1990) having no children. The lowest level of childlessness (17.9%) by age 30 years was for those born in 1941. The percentage of women who remained childless in 2020 by the end of their childbearing years, has remained fairly consistent since the late 1950's, with 18.1% of the latest cohort born in 1975 having no children. This suggests that women are delaying childbearing rather than not having children.

Cohort

A group of women with the same year of birth.

Completed family size

The average number of live-born children for women who are assumed to have completed their childbearing.

Childlessness

The proportion of women who had not had a live birth by a specific age. No distinction is made between voluntary and involuntary childlessness (no distinction is made between childless and childfree women).

Exact age

The ages of women are presented in "exact years". Therefore, figures should be interpreted as the average number of children a woman has had up to that birthday. Childbearing up to exact age 30 years includes cumulative fertility through a woman's lifetime up to the day before her 30th birthday.

Standardised mean age

The standardised mean (average) age is a measure that eliminates the impact of any changes in the distribution of the population by age and therefore enables trends over time to be analysed. Standardised means are calculated using rates per 1,000 female population by single year of age of mother.

Further definitions are available in the glossary of terms in our User guide to birth statistics.

Quality

Births Quality and Methodology Information (QMI) on strengths, limitations, appropriate uses, and how the data were created is available.

Birth statistics are derived from information recorded in England and Wales when live births and stillbirths are registered.

In this release, the number of children is based solely on the number of live-born children a woman has had. Stillbirths, adopted, fostered or stepchildren are excluded.

A woman's childbearing is assumed to start at age 15 years and end at age 45 years (the day before her 46th birthday). A small number of women complete their childbearing after this, but these do not affect the overall patterns. Births to women aged 45 years and older are included in the supporting dataset.

Coronavirus and birth statistics

The data in this publication may be affected by the coronavirus (COVID-19) pandemic as they relate to births for the year ending 31 December 2020. In March 2020, birth registrations in England and Wales were temporarily suspended. Since June 2020, birth registrations have restarted where it is safe to do so. Normally, births are registered within 42 days, but was only true of 58% of births in 2020. Any late registrations will be included in the 2021 births data release, as is normal practice. For more information, please see our User guide to birth statistics and Births in England and wales explained: 2020.

Our User guide to birth statistics provides further information on data quality, legislation and conceptual procedures.

This release presents statistics on childbearing among women in England and Wales by the year of birth of the mother. The year is approximate and based on calendar year of occurrence and age of mother at childbirth. For instance, women aged 32 years, giving birth in 2012 could have been born in 1979 or 1980; but are regarded as the 1980 cohort.

Current registrations do not collect data on the number of previous children a man has had, preventing the calculation of the proportion of men who have not fathered a child. A man's reproductive span is not as well-defined, so would need a longer time series to calculate cohort measures. Male period fertility rates can be found in Birth characteristics in England and Wales.

National Statistics status for Births in England and Wales

National Statistics status means our statistics meet the highest standard of trustworthiness, quality and public value, and it is our responsibility to maintain compliance with these standards.

Our most recent UK Statistics Authority full assessment that was published in September 2011 is available to view. A number of improvements have been made since the last review.

• We have explained revisions to the way statistics are produced in the User guide.
• With any corrections made, we have explained the change and why it has been made.
• Background information has been added to the User guide and QMI about the differences between UK countries' methods.
• Changes were made in 2018 to the way birth statistics are published.

In 2012, changes were made to the Population (Statistics) Act 1938; information on the number of previous children and whether a woman was previously married is now collected from all mothers. In 2016, the registration system was updated to allow the collection of this data.