"The 2018 general fertility rate fell to another all-time low for the United States," the researchers wrote in the report, published Wednesday.
The report found that the general fertility rate dropped 2% between 2017 and 2018 among girls and women age 15 to 44 nationwide.
In 2017, the total fertility rate for the United States continued to dip below what's needed for the population to replace itself, according to a separate report published by the National Center for Health Statistics in January.
America's fertility rate and the number of births nationwide have been on the decline in recent years. A report of provisional birth data published by the National Center for Health Statistics in May showed the number of births last year dropping to its lowest level in about three decades.
Now the center's latest report presents selected highlights from that 2018 birth data.
For the report, researchers examined birth certificate data from the National Vital Statistics System's Natality Data File, taking a close look at births among white, black and Hispanic women in 2018.