A new government study has shown that there is a "noticeable trend" between young women who fall pregnant by 18 and their GCSE results.
A third (33%) of 18-year-olds who had gained between one and four GCSEs at grades D-G had been pregnant at least once, compared to 6% of those who scored eight or more GCSEs at grades A*-C.
Published by the Department of Education, the study showed that of the 18% who had been pregnant, almost eight in 10 (79%) had been expecting a baby on just one occasion, nearly one in five (18%) had been pregnant twice, and 3% had been pregnant at least three times.
More than a third (36%) decided to have an abortion, while just under half (46%) of those who had been pregnant by the time they were 18 decided to keep their baby.
The Youth Cohort Study and the Longitudinal Study of Young People in England analysed the responses of thousands of 18-year-olds across the country.
Chair of the Teenage Pregnancy Independent Advisory Group, Gill Frances, said: "We still have unacceptably high levels of teenage pregnancy in this country although rates are at their lowest for 20 years.
"We need to do more to help young people get easy access to reliable long-acting contraception and to identify and support those most at risk of early pregnancy.
"At a time of public spending constraints, these statistics are a reminder that it is critical to maintain investment in young people's contraceptive and sexual health services."