Researchers found that pattern stuck even after they took into account the girls' race and poverty in their neighborhoods - both of which are tied to teen pregnancy rates.
Poor academic skills may play into how teens see their future economic opportunities and influence the risks they take - even if those aren't conscious decisions, explained Upadhya, who wasn't involved in the new research.
Dr. Ian Bennett from the University of Pennsylvania and his colleagues looked up standardized test reading scores for 12,339 seventh grade girls from 92 different Philadelphia public schools and tracked them over the next six years.
During that period, 1,616 of the teenagers had a baby, including 201 that gave birth two or three times.
Hispanic and African American girls were more likely than white girls to get pregnant. But education appeared to play a role, as well.
Among girls who scored below average on their reading tests, 21 percent went on to have a baby as a teenager. That compared to 12 percent who had average scores and five percent of girls who scored above average on the standardized tests.
Once race and poverty were taken into consideration, girls with below-average reading skills were two and a half times more likely to have a baby than average-scoring girls, according to findings published in the journal Contraception.
Birth rates among girls ages 15 through 19 were at a record low in the U.S. in 2011 at 31 births for every 1,000 girls, according to the Centers for Disease Control and Prevention. But that rate is still much higher in minority and poorer girls than in white, well-off ones, researchers noted.
And in general, it's significantly higher than teen birth rates in other wealthy nations.
Teen pregnancies are a concern because young moms and their babies have more health problems and pregnancy-related complications, and girls who get pregnant are at higher risk of dropping out of school.
Upadhya said the answer to preventing teen pregnancy in less-educated girls isn't simply to add more sex ed to the curriculum.
"This is really about adolescent health and development more broadly, so it's really important for us to make sure that kids are in schools and in quality educational programs and that they have opportunities to grow and develop academically and vocationally," she told Reuters Health.
"That is just as important in preventing teen pregnancy as making sure they know where to get condoms."
SOURCE: http://bit.ly/TcHB0s Contraception, online December 13, 2012.