Less contraception advocacy seems to encourage more teenage pregnancies.
The U.S. teen birth rate rose for a second straight year in 2007 after a long decline and more babies were born to all mothers than even at the peak of the baby boom after World War Two, officials have said.
In an encouraging development, the rate of premature births and low birthweight babies declined after a long upward trend, according to a report by the Centers for Disease Control and Prevention's National Center for Health Statistics.
But Cesarean deliveries rose for an 11th straight year to a new high - up 2% to 31.8% of births.
"Every pregnant woman in the U.S. should be alarmed by this rate," Pam Udy, president of the International Cesarean Awareness Network advocacy group, said in a statement. "Half or more of Cesareans are avoidable and over-using major surgery on otherwise healthy women and babies is taking a toll."
A record 39.7% of babies in 2007 were born to unmarried women, including 71.6% of black babies and 51.3% of Hispanic babies, the report found.
The birth rate for teenage girls rose 5% between 2005 and 2007, according to the report.
The previously reported increase in 2006 ended 14 straight years of declines. The rate rose again in 2007 by 1% over the prior year to 42.5% per 1 000 girls aged 15-19.
Some experts blame the teen birth rate increases on the government's support for "abstinence-only" education under the Bush administration that left office in January, but advocates of that approach have defended it as sound.More sex, less birth control
"The teen birth rate in the U.S. had declined dramatically in past years because of both less sex and more contraception," Bill Albert of the National Campaign to Prevent Teen Pregnancy advocacy group said in a telephone interview.
"The teen birth rate is now going up probably for the opposite set of reasons - the combination of more sex and less contraception."
According to the Child Trends nonprofit research group, fewer sexually active high school girls are using contraceptives and fewer U.S. students are getting formal contraceptive education.
"Two years of increases in the teen birth rate are a wake-up call showing the need to target efforts to help teens delay sexual activity, improve contraceptive use, and delay early and generally unplanned childbearing," said Jennifer Manlove of Child Trends.
The total of 4.3 million babies born in 2007 was the most ever recorded in the United States, topping even the peak of the baby boom in 1957, according to the report.
The percentage of babies born prematurely rose by more than a third since the 1980s but dropped by 1% in 2007 compared to the previous year.
Premature babies - defined as born before the 37th week of pregnancy instead of the typical pregnancy of roughly 40 weeks - are more likely to have medical and developmental problems.
The March of Dimes charity said pre-term birth is the leading cause of newborn deaths in the United States, with early births costing more than $26 billion annually.
For the first time since 1984 there was a drop in the percentage of babies born with low birth weight, which similarly increases the risk of a baby's health problems.What do you think about the climbing teen pregnancy rate?