The survey included thousands of white, African-American, and Hispanic teen girls, living in 19 states, who gave birth between 2004 and 2008.
Among the findings:
Nearly a fourth (23.6%) of the teens who did not use birth control said it was because their partners did not want to.
Twenty-two percent said even though they did not set out to have a baby, they would not mind if they got pregnant.
Teens in five states were asked about their use of specific contraceptives. About 24% used condoms, about 20% used oral contraceptives, and about 5% used highly unreliable methods such as rhythm and early withdrawal.
Hispanic teens were the most likely to mistakenly believe that they could not get pregnant at the time their babies were conceived, with 42% reporting this, compared to 32% of African-Americans and 27% of whites.
About 1 in 4 white and Hispanic teen moms and 1 in 5 black teen moms said they did not use birth control because their partners did not want to.
Teen Birth Rate Declining, But Still High
While fewer teens overall are having babies in the United States, the teen birth rate is still among the highest of any developed country. In 2009, close to 400,000 teens in the U.S. gave birth, the CDC says.