Puberty and teenage pregnancies: the facts

PUBERTY is arriving earlier for both girls and boys, due to improvements in nutrition - puberty is triggered by attaining a certain body mass. In 1900 the average age for girls to start menstruating was 16. By 1950 it had fallen to 141/2, and by the 1980s to just over 13. There is evidence to suggest that now it is even lower, with a quarter of girls menstruating by their final year of primary school. It is harder to ascertain when boys reach puberty, but it may be as young as 10, as opposed to between 11 and 14 a few decades ago.

Despite these changes, the numbers of very early teenage pregnancies has remained fairly stable: 15-35 13-year-olds and two or three 12-year- olds per year and an 11-year-old every couple of years, according to the Office for National Statistics.

According to the Brook Advisory Centre, overall numbers of teenage conceptions in Britain have fallen; since 1990 there has been a reduction of 15 per cent among 15-19 year olds, and 16 per cent among under-16s (although England and Wales still top the European league). This may partly be due to an increase in young people's contraception services.