'Sibling effect' raises teenage pregnancies
Young motherhood 'contagious' among sisters
TEENAGE pregnancy could be 'contagious' and 'caught' by girls influenced by their elder sisters who have children while young, new research suggests.
A team studied the records of thousands of women and their families over decades and found that those with elder sisters who had children in their teenage years were twice as likely to do the same as those without.
The research by British and Norwegian scientists showed that although there is evidence that better education of women leads to lower teenage pregnancy rates, in families with teenage mothers the chances of a younger girl having a child in her teens doubled from one-in-five to two-in-five.
The scientists believe their research shows that new policies, which take into account this 'sibling effect', are needed to tackle teenage pregnancies.
The University of Bristol's Professor Carol Propper, who co-authored the study, said: "Previous research has shown that family background and raising the education of girls decreases the chances of teenage pregnancy.
"However, these findings reveal the positive sibling effect (on conception rates) still dwarfs the negative effect of education. These findings provide strong evidence that the contagious effect of teen motherhood in siblings is larger than the effect of better education.
"This suggests that more policies aimed directly at decreasing teenage pregnancy may be needed."
The study saw Prof Propper work with scientists from the University of Bergen and the Norwegian School of Economics. They analysed census data from 42,606 Norwegian women who were born after World War Two, and their families, as they got older.
They chose to look at sister-to-sister relationships because sisters generally spend more time together than with friends and are therefore likely to be influenced by their siblings.
There is also scientific evidence that suggests younger children in families are influenced by the sexual activity of their older brothers and sisters.
They found that the sibling effect is larger for women from poorer backgrounds but gets smaller as the age gap between sisters increases.
Figures released by the UK's Office for National Statistics (ONS) in February showed that in 2009, the rate of conception among women aged 18 and under decreased by 5.9pc, from 40.7 conceptions per thousand women aged 15-17 in 2008 to 38.3 in 2009. Conception rates for women aged under 20 decreased by 4pc.
There has been a decline in teenage pregnancy rates since 1998, apart from small increases in 2002 and 2007. Almost half (49pc) of pregnant women under 18 had an abortion.
This continues the overall downward trend observed since 1998. For women aged under 18, the proportion of conceptions leading to a legal abortion was unchanged in 2009 at 49pc.