Population Fertility in Lancashire
2006

Introduction

A common measure of population fertility is the "Total Fertility Rate" (TFR). This provides a single measure of fertility and is the average number of children that a woman would have if she experienced the age-specific fertility rates of a particular year for her entire childbearing years. So the TFR is commonly used to look at fertility because it standardises for the changing age structure of the population.

Results

In 2006 the total fertility rate in the UK was 1.84 children per woman. Whilst well below the so-called "replacement level fertility" (see below) this rate was up from 1.79 in the previous year and was the fifth consecutive annual increase from a low point in 2001 when the TFR was at a record low of 1.63. The last time the TFR reached the 2006 rate was 26 years previously in 1980. Although the current level of fertility is relatively high compared with that seen during the 1990s it was considerably higher during the 1960s 'baby boom' when the TFR peaked at 2.95 children per women in 1964.

There have been increases in fertility rates for all age groups but much of the recent upturn appears to have been driven by increasing birth rates among older women in their thirties and forties. For example fertility rates for women aged 30-34 rose from over 78 live births per thousand women in 1986 to nearly 105 in 2006. Also, the fertility rate for women aged 40 and over has more than doubled over the same period. These changes in the age pattern of fertility have led to steady increases in the average age at child bearing. The average age for giving birth in the UK has increased from 28.6 years in 2001 to 29.2 years in 2006. There has also been a continued rise in the proportion of births to mothers born outside the UK – to more than a fifth: in 1996 just 12.8% of births were to non-UK born mothers.

Across the UK in 2006 there was a large range in fertility rates between districts. These ranked from a 'high' of 2.80 children per woman in Rutland Unitary Authority to just 1.20 in the London Borough of Kensington and Chelsea.

Patterns of fertility in the Lancashire sub-region have largely followed those nationally and in 2006 appeared to be slightly higher than the UK or England and Wales averages though there were marked variations across the area (Table 1). The highest TFR by far was to be found in Blackburn with Darwen, its rate of 2.45 being a third higher than the UK average. Indeed, Blackburn with Darwen's TFR was the fourth highest in the whole of the UK. A number of other local districts, all in East Lancashire, also ranked highly in a national context including Hyndburn (19th highest), Pendle (20th) and Burnley (47th). Conversely, TFRs were far lower and well below the national average in Lancaster (1.41 and 10th from bottom in the UK), Ribble Valley (1.62), Fylde (1.66) and West Lancashire (1.82).

Replacement Level Fertility

The TFR can also be used as an estimate of the fertility growth factor in the population – that is whether the childbearing population is replacing itself from one generation to the next, other things being equal. In the UK and most other developed countries a TFR or completed family size of about 2.1 children per woman is required to maintain long-term population levels to take account of infant mortality and the unbalanced sex ratio at birth. It is important to remember that the level of 2.1 children is an average across all women: to ensure replacement fertility a substantial proportion of women need to have three or more children in order to compensate for those who remain childless or have only one child. Although migration can be a significant driver of population change, for the purposes of calculating replacement fertility migration is normally ignored. In Lancashire only those four East Lancashire districts referred to above with the highest ranking have TFRs at or above replacement fertility while Lancashire as a whole, like the UK itself, has a TFR below replacement level. In the UK fertility has been below replacement level since 1973.

Below replacement fertility can have important demographic and socio-economic implications but these consequences are only likely to arise with persistent long-term replacement fertility. In the case of Lancashire, net inward migration has for many years compensated for low fertility. For example, over the recent period 2001-2006 Lancashire's total population grew by an estimated 32,000 or by 2.3%. Of this growth, only 2,000 derived from natural change – the balance of births over deaths. All the remainder (+30,000) resulted from net inward migration flows.

This page was compiled by Peter Kivell.

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