Teenagers who have had an abortion most likely have been pregnant before, according to a recent study.

Researchers at the University of East Anglia found that nearly a quarter of teenagers in England and Wales who have had an abortion have been pregnant before, resulting in either a birth -- live or stillbirth -- or abortion.

"This information will help to guide more targeted interventions to continue the downward trend in pregnancy and to monitor the effectiveness of current sexual health priorities on reducing conceptions and unwanted pregnancies among this age group," Lisa McDaid, lead researcher of the study, said in a statement.

For the study, researchers collected and analyzed more than 20 years' worth of data from women between the ages of 15 and 19. They analyzed national abortion figures for England and Wales from 1992 to 2013. They aimed to more precisely estimate the number of teenagers having an abortion who have had one or more previous pregnancies.

In 2013, approximately 23 percent of teenage women having an abortion had been pregnant before. A minority, less than 5 percent, had two or more previous pregnancies, though this number almost doubled between 1992 (937) and 2002 (1,823).

During the period studied, the number of teenagers having an abortion as a result of a subsequent pregnancy increased by 33 percent, from 5, 260 in 1992 to 6631 in 2013. Most of this increase took place before 2004 and the figure appears to have stabilized. The number peaked in 2008, when 9, 834 had experienced a previous pregnancy.

"The continuing high proportion of teenagers who have an abortion following one or more previous pregnancies highlights the complexity of these young women's lives and we need to recognize that the circumstances of each pregnancy may be very different. Our results clearly demonstrate that young women who become pregnant can be considered a high-risk group for subsequent, unplanned, mistimed, or unwanted pregnancies, emphasizing the importance of embedding preventative actions and behaviors among this group after a birth or abortion," McDaid said.

The findings are detailed in the Journal of Adolescent Health.