March 18 (Bloomberg) -- The number of teenagers having babies rose for the second straight year in 2007, at a slower pace than the previous 12 months, a U.S. government report showed.

The birth rate for teens increased about 1 percent in 2007 from 2006, following a 2.8 percent rise in 2006, according to the report from the U.S. Centers of Disease Control and Prevention. The number of unmarried women having babies also rose, accounting for almost 40 percent of all births in 2007, the report said.

Babies born to teenage mothers are more likely to be premature and less healthy, according to the March of Dimes. Government and nonprofit programs work to provide education on contraception, encourage youth to postpone sexual relationships and promote abstinence to reduce the rate of teen births, which had declined for 14 years until 2006.

“It is clear here that one of the jobs at hand is to get back on track to where we were, and that is convincing more young people of the value of delaying sexual activity and convincing sexually active teens to use contraception consistently and carefully,” said Bill Albert, a spokesman for the National Campaign to Prevent Teen and Unplanned Pregnancy in Washington.

The reasons behind the increase in teen births are unclear. Some policy experts attributed the rising pregnancies to a lack of education about contraception as the U.S. government focused on abstinence-only programs under former President George W. Bush. Others cited an ill-advised confidence after years of progress.

Redoubling Efforts

“It may be after 14 straight years of continuous progress that complacency may have crept in. Policy makers, program people, practitioners, need to redouble their efforts here and focus again on teen pregnancies and birth,” Albert said.

A CDC survey, which is expected to be released later this year, may provide a clearer picture about sexual activity, contraceptive use and sexual behavior for all age groups, said Stephanie Ventura, one of the authors of today’s report.

“It’s certainly some cautionary data that should cause everyone working to prevent teenage pregnancies and birth to take pause,” said David Landry, a senior research associate at the New York-based nonprofit Guttmacher Institute. “The federal response to reducing teenage pregnancy should be more aggressive and should be more evidence-based than it has been in the past.”

Births Crept Up

Today’s study found that the birth rate for teens was 42.5 births per 1,000 females ages 15 to 19 in 2007, up from 41.9 in 2006. The birth rate for girls ages 10 to 14 was unchanged.

“The increase in 2007 is much smaller, only 1 percent. That’s a little bit of good news, but it’s still an increase,” said Ventura, chief of the reproductive statistics branch of the CDC’s National Center for Health Statistics, based in Hyattsville, Maryland, which conducted the study. “It’s really hard to say what’s going on. We just need more information about the factors that would be associated with this and that’s not information we have on birth certificates.”

Susan Malley, an obstetrician and gynecologist at Westchester Health in Katonah, New York, north of New York City, said the U.S. government needs to provide money for health education that teaches abstinence and contraception use, rather than abstinence alone.

“By denying that teens are having sex, we’re burying our heads in the sand,” she said.

The total number of births in 2007 increased to 4.32 million, the highest number ever registered in the country, the CDC said. Birth rates rose for women in their 20s, 30s and early 40s.

Single Women

The number of unmarried women of childbearing age who gave birth reached historical levels in 2007, up 3 percent to 5 percent from 2006, according to the report. About 1.71 million babies were born in 2007 to unwed mothers of all ages.

Almost 60 percent of all births to women ages 20 to 24 were to unmarried mothers and 32 percent of all births to women aged 25 to 29 were to unmarried mothers, the report showed.

The report also found that the percentage of low birth weight babies declined for the first time since 1984 and the number of preterm births also fell.

To contact the reporter on this story: Nicole Ostrow in New York at nostrow1@bloomberg.net.

Last Updated: March 18, 2009 12:00 EDT