Research Type: Reproduction, Fertility & Pregnancy

The project ‘Understanding Recent Fertility Trends in the UK and Improving Methodologies for Fertility Forecasting’ will examine the significant fluctuations in fertility levels in the UK in the last two decades, will investigate their causes, and will develop improved methodologies for fertility forecasting. The last two decades have witnessed dramatic changes in fertility levels, which were not predicted by demographers or government statisticians: Fertility significantly increased in the first decade of the 21st century, whereas it has declined thereafter.  These changes when translated into numbers of births, have had important implications, for example in the provision of health services, childcare, and school places. The project aims, first, to produce detailed measures of fertility changes in recent years in the UK. Second, it will decompose the overall changes into those attributable to compositional changes in the UK population, e.g. by country of birth, migrant population, education, and those which are attributable to behavioural changes over time, i.e. women have fewer or more children. Finally, these insights will be used to develop new methodologies for more accurate forecasting of fertility applying them to the UK and its constituent countries. The developed methodologies could be applied to project fertility trends in other industrialised countries.

This is a development of the NILS022 project where a statistical analysis was based upon a panel of women aged 15-44 over the period 1997-2007 that was constructed from the NILS. A similar methodology is proposed; the statistical analysis consists of a panel logit analysis of whether a birth occurs in a period; the explanatory variables will include parity, duration, religion and locality variables.

The UK has the highest rates of teenage pregnancy in Western Europe and while these have been gradually falling across the UK (including NI) since 2002, rates of pregnancy for girls aged less than 20 remains high. While it is acknowledged that not all teenage pregnancies are unintended and that the life course for teenage parents is not necessarily negative, unintended pregnancy remains a major component of adolescent pregnancies and can risks considerable adverse health problems for teenagers and their infants as well as generating enormous emotional, economic and social costs1 for adolescents, their families and society globally.

The project builds upon the earlier study NILS 022, Predicting Short Run Changes in Fertility in Northern Ireland. The project assembled a panel of women from 1997 – 2007 aged between 16 and 44 years in each year, together with their characteristics drawn from the 2001 census and the births they had each year from the GRO. The analysis was based on the logit model with time dummies employed as the basis of the forecast model. This was unsatisfactory due to the importance of the trend element in the forecast – essentially the projection of the trend into the future was arbitrary.