(CBS/AP) More teenage girls are waiting longer to have sex, according to a new report, and for those who have sex, more are using contraception.
A new survey of 2,300 teen girls ages 15 to 19 that's published in the CDC's journal Morbidity and Mortality Weekly Report found 57percent of them never had sex. That's up from a 49 percent rate in 1995.
The survey also found 60 percent of teen girls who have sex use the most effective kinds of contraception, also up from the mid-90s, when less than half were using the best.
The most effective forms of birth control were the pill, patch, vaginal ring, IUD, arm implant and contraceptive shot. Using only condoms was deemed only moderately effective.
Health officials say the trend may help explain a large decline in the U.S. teen birth rate since 1990.
The new findings may also signify more awareness about pregnancy risk. A CDC survey of 5,000 teen moms who had unexpected pregnancies that was published in January 2012 found a third of them didn't use birth control because they didn't believe they could pregnant,reported. Reasons they gave included they thought they couldn't get pregnant the first time they had sex, didn't think they could get pregnant at that time of the month or thought they were sterile.
The National Institutes of Health has more resources on teen pregnancy.