5. Age at conception

Between 2011 and 2012 conception rates increased for women aged 35 years and over, and decreased for women aged under 35 years.

The largest percentage increase in conception rates occurred among women aged 35-39 (1.0%). A smaller increase in conception rates was recorded among women aged 40 and over (0.7%). Conception rates for women aged under 20 and 20-24 decreased by 9.6% and 5.5% respectively. Rates for women aged 25-29 and 30-34 decreased by smaller amounts (1.5% and 2.3% respectively).

Figure 2: Relative changes in age-specific conception rates, 1990-2012 England and Wales Source: Office for National Statistics Download this chart Figure 2: Relative changes in age-specific conception rates, 1990-2012 Image .csv .xls

The conception rate for women aged 40 and over has more than doubled since 1990 (Figure 2) from 6.6 to 14.0 conceptions per thousand women. The number of women in this age group conceiving has risen from 12,032 in 1990 to almost 29,000 in 2011 and 2012. For women aged 40 and over, the percentage of conceptions leading to abortion fell from 43% in 1990 to 28% in 2010, 2011 and 2012. The number of conceptions, the conception rate and the percentage of conceptions leading to abortion for women aged 40 and over have remained relatively stable in 2012, compared with 2011.

The conception rate for women aged 35-39 has seen similar increases, almost doubling since 1990. The 30-34 age group is the youngest age group in which conception rates have risen almost continuously since 1990, rising by over a third.

Reasons for an increased number of women conceiving at ages 30 and above include increased participation in higher education; increased female participation in the labour force, the increasing importance of a career, the rising opportunity costs of childbearing, labour market uncertainty, housing factors and instability of partnerships ( Jefferies, 2008 (297 Kb Pdf) ; Ní Bhrolcháin, 2012).

The conception rate for women aged under 20 fell by 9.6% to 44.2 conceptions per thousand women aged 15-19 in 2012 (from 48.9 in 2011). This continues the overall downward trend in the conception rate for women aged under 20 since 2007 from 61.4 conceptions per thousand women. In 2012 conceptions to women aged under 18 accounted for 37% of all conceptions to women aged under 20, unchanged from 2011.

In 2012 there were 27,834 conceptions to women aged under 18 compared with 31,051 in 2011, a decrease of 10%. This is the lowest number of conceptions in this age group since 1969. Nearly half (49%) of all conceptions to women aged under 18 in 2012 led to an abortion, this proportion has remained relatively unchanged since 2006.

The under 18 conception rate for England and Wales was 27.9 in 2012 compared with 30.9 in 2011, a decrease of 9.7%. This is the lowest estimated under 18 conception rate since comparable conception statistics were first produced in 1969. This fall in the conception rate in 2012 can be attributed to similar falls in the conception rate leading to abortion and the conception rate leading to a maternity (decreases of 9.9% and 9.5% respectively). The under 18 conception rate continues the overall decline recorded since 1998 when there were 47.1 conceptions per thousand women aged 15-17, despite slight increases in 2002 and 2007. Since 1998 the conception rate for women aged under 18 has decreased by 41%.

Figure 3: Under 18 conception rate, 1975-2012 England and Wales Source: Office for National Statistics Notes: Rates have been calculated using the latest population estimates ONS changed the methodology for estimating age at conception from 1997. Rates for 1987 to 1996 were revised to provide a comparable time series from 1987 onwards. The conception rates for 1975 to 1986 are not directly comparable as they have been calculated using the previous methodology for estimating age at conception. See background note 3 for more information Download this image Figure 3: Under 18 conception rate, 1975-2012 .png .xls

The number of conceptions to girls aged under 16 decreased by 9.3% from 5,991 in 2011 to 5,432 in 2012. A similar decline can also be seen in the conception rate for girls aged under 16. In 2012 there were 5.6 conceptions per thousand girls aged 13-15 compared with 6.1 in 2011, a decrease of 8.2%. This fall in the conception rate consists of an 11% fall in the rate of conceptions leading to abortion and an 8.3% fall in the rate of conceptions leading to a maternity. The percentage of conceptions leading to abortion for this age group has remained at 60% since 2011.

Overall the under 16 conception rate has decreased since 2007 from 8.1 conceptions per thousand girls aged 13-15 to 5.6 in 2012. The under 16 conception rate is the lowest since 1969, the first year for which we have comparable data, when a rate of 6.9 conceptions per thousand girls aged 13-15 was recorded. Nearly three-quarters (72%) of under 16 conceptions in 2012 were to girls aged 15.

There are a number of factors which could explain recent reductions in teenage conceptions, including: