Over the last decade England and Wales has seen an increase in the total fertility rate (TFR) from a low of 1.63 in 2001 to 1.9 in recent years. While the TFR measures the current quantum of childbearing it can be influenced by changes in the timing of childbearing. Potential drivers of the increase in the TFR include increasing fertility among older women, increasing fertility among women in their 20s and possible influence from government benefits (e.g. tax credits and maternity and paternity leave) (ONS, 2013).
It is also possible that immigration to England and Wales has influenced the TFR because migration and fertility can be considered as being interrelated events (Sobotka, 2008). Immigration increased through this time period with varying countries of origin and drivers of immigration (geopolitical instability/armed conflict and globalisation in the realms of education and employment). Immigration accelerated further after the accession of eight Central and Eastern European countries (‘accession eight’ countries), along with Cyprus and Malta, to the European Union in 2004. Immigration can impact on fertility in at least three ways.
Firstly, migrants tend to be in the key childbearing ages and therefore expand the population of women exposed to risk of birth. Between 2001 and 2007 there was an increase in the number of foreign-born women aged 20-24 years while the number of UK-born women in childbearing years decreased (Tromans et al., 2009). This same research also identified that births to foreign-born women accounted for around two-thirds of the increase in fertility between 2001 and 2007. Between 2001 and 2011 the proportion of total births to women born outside of the UK rose from 15% to 25% (Tromans et al., 2009; ONS, 2013). However, the overall TFR increase was mainly due to increasing fertility among UK-born women. This is a reflection of the number of UK-born women relative to the foreign-born population. A geographical match between local government areas where there has been a substantial increase in fertility, and areas where there has been a high rate of migration between 1986 and 2006, has been identified (Tromans et al. 2008).
Secondly, some migrant groups tend to have larger completed family sizes than the non-migrant population; Pakistani and Bangladeshi women have tended to have higher completed family sizes than UK-born women (Dunnell, 2007) and have been identified as being more likely to migrate for family formation (Dubuc, 2012).
Thirdly, the TFR can be inflated by a timing effect among recent immigrants’ if there is a propensity to give birth shortly after migration. In other European contexts an elevated level of fertility has been observed among immigrants to the host country; in France (Toulemon, 2004) and Sweden (Andersson, 2004) migrants have been identified as exhibiting a higher level of fertility following migration However, there are competing hypotheses on the association between immigration and fertility and also on the causes of associations where they have been identified. (Other work has identified that immigration is associated with decreased fertility in the time after relocation). There is a more limited range of research on the timing of fertility among recent immigrants to England and Wales.
Research on the increase in fertility in England and Wales has tended to focus on the first two of the three ways in which immigration can impact on fertility, both of which are concerned with the ‘quantum’ or level of fertility. The relative role of immigrant fertility timing is still largely unknown. Period indices of fertility, like the TFR, can be affected by changes in the timing of childbearing which are intrinsically related to the age of migrants entering a country and their childbearing patterns. In part, the lack of research on timing of fertility among immigrants reflects the paucity of suitable data for studying the arrival and (duration to) subsequent births among immigrants (Kulu, 2003).
Our research (Robards et al., 2013) has shown that combining linked administrative and census data provides life history data which can be used to answer questions related to the timing of fertility among immigrants to England and Wales. Inclusion of a question at the 2011 Census asking anyone born overseas the year and month of immigration provides scope for studying the timing of fertility among immigrants in the 2001-2011 period. Fertility research in England and Wales needs to take account of the changing timing of childbearing among the whole population, including immigrants. By focusing on the TFR, the timing effects of immigration and changes in childbearing preferences among UK-born women on the TFR may be missed.