TUESDAY, April 10 (HealthDay News) -- The number of American teens giving birth has dropped to an all-time low, federal health officials reported Tuesday.

"There has been a phenomenal drop in the last two years," said report lead author Brady Hamilton, a statistician with the U.S. Centers for Disease Control and Prevention's Division of Vital Statistics. "It went down 9 percent between 2009 and 2010 and that's big."

Hamilton said the teen birth trend is a part of a larger trend with the U.S. birth rate. The birth rate for all but older women has been dropping for some time, he said.

The current teen birth rate now stands at about 34 births per 1,000 women ages 15 through 19. That's a 44 percent drop in the rate since 1991, according to the report.

In 2010, teen birth rates by age and race and Hispanic origin were also lower than ever before, the CDC said.

Fewer babies were born to teens in 2010 than in any year since 1946. If the drop in teen births hadn't occurred, there would have been an estimated 3.4 million more births to teens from 1992 to 2010, the report said.

Despite these declines, the U.S. teen birth rate is still among the highest among industrialized countries, according to the report.

In looking to explain the dramatic drop in teen births in the last two decades, Hamilton said there's evidence that messages about sexual practices and the use of contraceptives have been successful.

"This is good news because it allows girls to have the opportunity to devote time toward education and preparing for adulthood," he said.

Teen birth rates fell in all but three states during the three years from 2007 to 2010 -- Montana, North Dakota and West Virginia. The birth rates may vary by state due, in part, to differences in populations by race, the researchers said.

Mississippi had the highest rate of teen births, at 55 per every 1,000 girls aged 15 to 19, followed by New Mexico at about 53 and Arkansas at 52.5. The best-performing states included New Hampshire at just under 16 per 1,000, Massachusetts at about 17, and Vermont at just under 18.

Teen birth rates in 2010 ranged from about 11 per 1,000 Asian and Pacific Island teens, to 23.5 for non-Hispanic white teens, to about 39 for American Indian or Alaska Native teens, to 51.5 for non-Hispanic black teens, and about 56 per 1,000 for Hispanic teens, according to the report.

Dr. Lawrence Friedman, director of adolescent medicine at the University of Miami Miller School of Medicine, called the new report "excellent news" and said it "represents the ongoing positive trend in the reduction of teen births."

According to the CDC, fewer teens are having sexual intercourse, Friedman said.

But Friedman said: "That doesn't mean there is less sexual activity. There's plenty of sexual activity -- oral sex and mutual masturbation and other things that don't produce pregnancies."

There's also increased use of contraception, Friedman said. "In addition, there is more awareness of the negative effects of pregnancy and sexually transmitted diseases," he said.

More information

For more on teen pregnancy, visit the U.S. Centers for Disease Control and Prevention.