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Fertility Assumptions

Fertility Assumptions

CSO statistical publication, , 11am

Fertility Assumptions Agreed

The following chapter contains the fertility assumptions agreed by the Expert Group and the issues considered in reaching their decision. Based on their analysis the Expert Group considered that the most likely outcome for overall average fertility over the projection period, as measured by the Total Fertility Rate (TFR), would be in the range 1.55 to 1.3. Taking into consideration the trend of the TFR in Ireland over the last number of years the trajectory was taken to start at 1.55 in 2023, decrease incrementally to 1.3 by 2038 and remain constant thereafter.

The main items deliberated on prior to reaching agreement are discussed in the subsequent sections, including:

  • Historical and recent trends in births
  • Age specific fertility rates
  • Number of women of child bearing age
  • Average age of first time mothers
  • Comparisons with other European countries

Historical and recent trends in births

The number of births each year in Ireland has varied over the past 50 or so years, the number of births peaked in 2009 reaching 75,550. Births have declined almost consistently since 2009, with fewer than 60,580 births recorded in 2021. The provisional number of births for 2022 and 2023 stand at 54,477 and 54,418 respectively, with the final figure for 2022 to be published in October 2024. See figure 4.1 below for a breakdown of the number of births per year.

Figure 4.1 Number of births, 2007 - 2021

Age specific fertility rates declining across most age groups in recent years

The main factors which impact on the number of births are the number of women of child bearing age (15 - 49 years) and their fertility levels. The total fertility rate (TFR) was as high as 4.03 in 1965 but it has fallen steadily thereafter. The age specific fertility rates (ASFR) also show a general decline with a rate of 228.7 for women aged 25 - 29 in 1970 down to 66.8 in 2021. Similar trends can be observed in all age groups, with those aged 30 - 34 falling from 201.9 to 124.2 in 2021 while the 20 - 24 age group fell to 28 (from 145.5 in 1970). See table 4.1.

Table 4.1 Age specific and total fertility rates, 1960 - 2021

Decline in the number of women of child bearing age

Not only are the age specific fertility levels declining, but the number of women in the younger age groups is also falling.  For example, the number of women aged 20 - 29 has been in decline in recent years, falling from 383,000 in 2009 to nearly 304,000 in 2022 (-20.6%), while the number of women aged 30 - 39 has remained almost static, with small fluctuations between 368,000 and 385,000 since 2012.  This can be compared to the period between 1991 and 2008 when the number of women aged 20 - 29 grew by almost 135,000 (52.7%) and the number of women aged 30 - 39 increased by 108,500 (44.3%).  The combination of declining fertility rates allied with a decrease in the number of women of child bearing age has resulted in the fertility rate falling from 2.10 in 2010 to 1.73 in 2021 or a decline of 17.6%.  See table 4.2 and fig 4.2.

Average age of first time mothers increasing

The Expert Group also noted that the age at which women are deciding to have their first child is rising year on year and that this would be expected to impact on future fertility rates if the trend were to continue. There has been an increasing trend towards later births, with the average age of first-time mothers rising by 5.7 years from 26 years in 1985 to 31.7 years in 2021.

Table 4.2 Number of females for selected age groups and years

Figure 4.2 Distribution of births by age of mother, 2008 - 2021

Comparison of Irish and European fertility rates

The Irish total fertility rate (TFR) is decreasing steadily and has reached 1.55 in 2022. This is slightly above the European average TFR of 1.46.

The decision taken by the Expert Group is that the total fertility rate will decrease from 1.55 to 1.3 by 2037 and then stabilise at this level until the end of the projection period in 2057. The Group considered that this assumption would allow Ireland to remain in line with the 2022 EU average fertility rate while still allowing a decrease to take place from the current level to match the trend that we have been observing in the data.