The birth rate among adolescent and young teen girls in the United States fell sharply in the 1990s, hitting a 58-year-low in 2002, the Centers for Disease Control and Prevention reported on Monday.

CDC researchers said the drop in births among girls aged 10 to 14 might be a sign that programs emphasizing abstinence and other forms of birth control were having an impact on this high-risk group.

They noted that the downward trend in births occurred despite a rise in the number of girls in this age group.

“A number of surveys have shown that in recent years fewer teenagers are sexually active, and they seem to be acting more responsibly,” said Fay Menacker, a CDC statistician and one of the authors of the study.

Young girls have a higher risk of delivering babies that are premature or have low birth weights. These young mothers also are more likely to suffer hypertension and eclampsia, a serious condition marked by convulsions and seizures.

There were 7,315 babies born to girls aged 10 to 14 in 2002, compared to 11,657 in 1990. The 2002 birth rate for this age group was 0.7 live births per 1,000 girls, one-half of the 1990 rate and the same rate as 1946.

“We are encouraged by our continued progress in reducing births to teens of all ages, but we’re particularly pleased to make this kind of progress in such a young and vulnerable group,” CDC Director Dr. Julie Gerberding said in a statement.

Blacks had the highest birth rate among girls in the study at 1.9 per 1,000, more than six times the rate for whites. The rate for Hispanics was 1.4 per 1,000, while Asians and Pacific Islanders had a much lower rate of 0.3 per 1,000.

Among the states, Maine had the lowest rate at 0.2 per 1,000, while Mississippi had the highest at 2 per 1,000.

The drop in births among adolescents and young teens mirrors a similar trend among older teenagers in the United States, which typically has one of the highest rates of teenage pregnancy in the world.