The US teen birth rate has decreased like never before, driven by sharp declines among African Americans and Hispanics since 2006.
Increased access to contraception and teenage pregnancy prevention programs aided the fall, according to the US Centers for Disease Control and Prevention.
The birth rate for all young women aged 15-19 in the United States dropped 61 percent from 1991 to 2014, going from 61.8 to 24.2 births per 1,000.
Most of the drop was seen in the past decade. "Nationally, from 2006 to 2014, the teen birth rate declined 41 percent overall," said the report. The largest decline was among Hispanics (51 percent), followed by blacks (44 percent), and whites (35 percent).
However, the CDC cautioned that the teen birth rate among Hispanic and black teens remains about twice as high as among whites, and that significant socioeconomic disparities remain.
"The United States has made remarkable progress in reducing both teen pregnancy and racial and ethnic differences, but the reality is, too many American teens are still having babies," said CDC director Tom Frieden.
When teenagers give birth, both the new mothers and their babies may face negative health, economic, and social consequences, the CDC said.
Overall, teen births are estimated to cost the United States about $9.4 billion each year.
"These pregnancies are usually unintended and the mothers face various socioeconomic disadvantages," said Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York.
"Teenagers often do not access good prenatal care and this can have a huge impact on the pregnancies."
Janay Scott, a women's health expert at the Long Island Jewish Medical Center in New York, called the CDC report "heartening," but added: "We should not take this as a clarion call to relax our efforts."
"It's not just about the education of anatomy, rather it is empowering teens with knowledge about their bodies and how things work, then to go several steps further," said Scott.
"Our continued high rate of unintended pregnancy in the US makes 'magical thinking' -- believing that just 'say no' will work -- not realistic."