Research Programme

Measuring and accounting for fertility trends

Máire Ní Bhrolcháin, Eva Beaujouan

Project summary


The aim of this research was to measure and account for the trend towards later childbearing. It examined the potential causes of later and lower fertility in Britain and France by applying the framework put forward by Ní Bhrolcháin and Dyson (2007). While later childbearing is prominent in recent fertility trends in developed countries, a clear explanation had not been uncovered; the growth in educational participation is often mentioned as a potential cause, but explicit evidence of its role was sparse.


The research adopted a period approach and confined analysis to the first birth. This was because in both Britain and France later childbearing in recent decades was due entirely to later first births. Two sources of data were used; for Britain, a pooled series of General Household Survey (GHS) rounds from 2000 to 2007 were used - a subset of a larger time-series data-file of GHS surveys from 1979 to 2007 compiled by the Centre for Population Change. For France, the Family History Survey (FHS) linked with the French census of 1999 was used.In both the GHS and the FHS, a question was asked about the age at which respondents finished continuous education and this age was coded in completed years. It reflects the first age at which a person ceased to be in education or training, and not the age at which people later returning to education ultimately finished. This information was used to find out whether a respondent was in education at specified ages and dates.


The research showed that the rise in enrolment in education and training has substantially contributed to later childbearing in Britain and France. The results show that, in the early 1980s to the late 1990s, the longer time spent in education accounts for a sizeable part of the change in timing of first birth. The average age of a woman having her first child in 2004 was 27 years-old, three years later than in 1974, when the average age was 24 years old. During the course of these three decades, young men and women were progressively staying longer at school and also going into further and higher education in greater numbers, with women completing their education or training at an increasingly later age. In the late 1970s, young women were leaving full-time education or training at an average age of 18 years old, but by 2004 this had risen by two years to an average age of 20 years old.

During the period studied, the mean age of women having their first birth rose by almost one-and-a-half years. During the same period, the time between women leaving full-time education and a first birth only rose by 0.6 years. This means that about three fifths of the change in age at first birth in Britain is due to more time being spent in education and training (the figure is four fifths in France). In changing the measurement point to when young women leave full-time education or training, the delay to motherhood, compared across the decades, is much less than if we look purely at the differences in their ages at their first birth.

The findings suggest overall that if educational expansion is a driver for later childbearing, then the root cause of changing fertility trends lies not in the cultural domain, but in macro-economic and structural factors.



Beaujouan, E. and Ní Bhrolcháin, M. (2011) Cohabitation and marriage in Britain since the 1970’s Population Trends, 145, 35-59

Ní Bhrolcháin, M. and Beaujouan, E. (2012) Fertility postponement is largely due to rising educational enrolment Population Studies, 66, (3), 311-327


Media activities

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