Dec. 6 (HealthDay News) -- For the first time in 14 years, the number of teenagers having babies in the United States rose last year, according to a new government report released Wednesday.

That startling news was accompanied by additional data showing that last year also had record high rates for unmarried women having babies as well as for Caesarean deliveries.

The findings are in preliminary birth statistics compiled by the U.S. Centers for Disease Control and Prevention and were based on 99 percent of all births in 2006.

"Any increase in teen pregnancy and teen births is significant and a cause for real concern," said Bill Albert, the deputy director of the National Campaign to Prevent Teen and Unplanned Pregnancy. "I wouldn't call it a trend, but it's an alarming wakeup call," he added.

Albert thinks the increase in teen pregnancy is partly due to waning attention to the problem. "When you have a difficult social problem like teen pregnancy, it requires constant attention," he said. "The focus on teen pregnancy and teen births has lessened, because the news has been so consistently good since 1991."

Between 2005 and 2006, the birth rate for girls 15 to 19 rose 3 percent, from 40.5 births per 1,000 in 2005 to 41.9 births per 1,000 in 2006. This comes after 14 years of declining rates. During that time, teen births dropped 34 percent from a peak of 61.8 births per 1,000 in 1991, according to the report.

The biggest increases for 2006 were among black teens, where the rate rose 5 percent, followed by 4 percent for American-Indian teens, 3 percent for white teens and 2 percent for Hispanic teens.

"It's way too early to know if this is the start of a new trend," Stephanie Ventura, head of the Reproductive Statistics Branch at the CDC, said in a prepared statement. "But given the long-term progress we've witnessed, this change is notable."

However, the birth rate continued to drop for girls 10 to 14 years old. The birth rate in this group dropped from 0.7 to 0.6 per 1,000, and the number of births fell 5 percent to 6,405, the CDC reported.

For girls 18 to 19 years old, the rate of births is more than three times higher, at 73 births per 1,000, than the rate for teens 15 to 17, at 22 per 1,000. Among teens in the latter group, the birth rate rose 3 percent between 2005 and 2006. For teens 18 and 19, the birth rate rose 4 percent during the same year.

In addition, births among unmarried women were at a record high in 2006. Births to unmarried mothers increased almost 8 percent to 1,641,700 in 2006. This was a 20 percent increase from 2002, when the trend of increased births among unmarried women started. The largest increase, 10 percent, was among women 25 to 29, according to the report.

Overall, the birth rate among unmarried women rose from 47.5 births per 1,000 in 2005 to 50.6 per 1,000 in 2006. That's a 7 percent increase in one year and a 16 percent increase since 2002, the report said.

Moreover, births to unmarried mothers increased to 38.5 percent, from 36.9 percent in 2005.

Other findings in the annual report include:

• Caesarean deliveries rose 3 percent in 2006, to a new high of 31.1 percent of all births. In the last 10 years, the number of Cesarean deliveries has increased 50 percent.
• Total births in the U.S. rose 3 percent in 2006 to 4,265,996, a 3 percent increase from 2005.
• Birth rates also increased among women in their 20s, 30s and early 40ss.
• Preterm birth rates rose from 12.7 percent to 12.8 percent between 2005 and 2006. Babies delivered before 37 weeks have risen 21 percent since 1990.
• The percent of low birthweight infants rose from 8.2 in 2005 to 8.3 in 2006. The rate has increased 19 percent since 1990.
• The increased birth rate has increased the total fertility rate, which is an estimate of the average number of births that a group of women have over their lifetime. This rate increased 2 percent in 2006, to 2,101 births per 1,000 women. The rate is the highest since 1971, the first time since that year that the fertility rate was above "replacement" -- the level at which a given generation can replace itself.

SOURCES: Bill Albert, deputy director, National Campaign to Prevent Teen and Unplanned Pregnancy, Washington, D.C.; Dec. 5, 2007, report, U.S. Centers for Disease Control and Prevention, Births: Preliminary Data for 2006