THE FERTILITY rate of Irish women is likely to have been substantially underestimated over recent years due to women delaying childbirth until later in life, new research from the Economic and Social Research Institute shows.
This would have major implications for official population projections and could translate into a natural increase of more than 400,000 people over the coming decades.
As a result, policymakers may in fact be significantly underestimating the number of school places, childcare places and other essential public services needed into the future.
Official figures indicate the total fertility rate – the number of children a woman will have in her lifetime – for Irish women or long-term residents fell to about 1.83 in 2006.
However, Dr Pete Lunn of the ESRI says a detailed analysis of the fertility rate suggests that official figures do not take into account the shift towards childbirth in later life. He estimates the total fertility rate for Irish women may be as high as 2.2.
“The official figures appear to have mistaken a delay in childbirth for a reduction,” Dr Lunn said. “This so-called ‘tempo effect’ has also been a feature in other European countries.”
There has been a steady rise in maternal age for Irish women over decades. The average age for a woman giving birth in Ireland reached 32 years in 2010, up from 28 year in 1990. This is the oldest maternal age in the EU. Ireland also has the highest fertility rate in the union.
If the underestimate of fertility is as great as expected, it would dramatically affect our population growth.
Central Statistics Office projections drawn up in 2008 assumed two scenarios for Irish fertility over coming decades: a low scenario of 1.6 children per woman, and a high scenario of 1.9.
Based on calculations by Dr Lunn, even the high scenario of population growth would be a significant underestimate of the likely increase.
“These increases in population would take several decades to filter through,” he said. “It’s a bit like filling a bath: the flow of water may be greater than the water leaving the plug-hole, but it will still take quite a while for the water to rise.”
However, he said the recession and emigration could still reduce the fertility rate over the coming years.
“The very deep recession could yet bring such a drop in completed fertility about, though there are no signs of that yet,” Dr Lunn said. “Ireland has a history of huge swings in migration, so we can’t take anything for granted,” he said.
The findings are contained in an appendix to a report published last week, Households and Family Structures in Ireland: A Detailed Statistical Analysis of Census 2006.
The figures on fertility rates used in the study are based on Irish women who have been resident here since the 1990s. When more recent migrant women are factored in, it pushes the overall fertility rate higher still.
Minister for Children Frances Fitzgerald has expressed interest in the findings and said policy-makers will need to keep population growth assumptions under close review.
The likely change in fertility in Ireland means there is less of a need to pursue policies to encourage parents to have children, as has been the case in many European countries.
However, it would place more pressure on the State to deliver more school places, childcare services and other essential public services, at a time when public finances are under severe pressure.
The potential underestimate in fertility has been the subject of significant research internationally over recent years. Increasingly, scholars are concluding that while fertility undoubtedly fell to low levels in many developed countries in the late 20th century, estimates of very low fertility were probably exaggerated by delayed childbirth.
These delays led to exaggerated dips in the total fertility rate during the late 1990s, which were then followed by increases in fertility in the decade following the year 2000 as women who delayed childbirth began to have children.
