The US birth rate falls by four percent between 2007 to 2009, says study. Birth rates fell for all women under age 40, with some of the steepest declines seen in women in their peak childbearing years, according to the study by the National Center for Health Statistics (NCHS).
Among women aged 20 to 24, birth rates plunged by nine percent to reach 96.3 births per 1,000 women -- a record low for the age group.
Teen birth rates declined by eight percent to just over 39 births per 1,000 girls and young women, the lowest rate ever recorded for those in the 15-19 age bracket.
The birth rate among women aged 25-30 dropped by six percent, and for women between 30 and 40, by two percent.
Women of all ethnic and racial origins were having children at a slower pace, but Hispanic women saw the largest drop, nine percent, compared to three percent for non-Hispanic white women and four percent for non-Hispanic black women, the NCHS said.
The authors of the report, which analysed data from US vital statistics natality files, said it was "not possible with birth data alone to identify the factors shaping the fertility rate decline."
But they cited a study published last year by the Pew Research Center, which noted that the drop in fertility coincided with deteriorating economic conditions in the United States.
"There is a strong association between the magnitude of fertility change in 2008... and key economic indicators including changes in per capita income, housing prices and share of the working-age population that is employed across states," said the Pew report.
Its researchers looked at fertility rates and economic indicators in 25 states, and found that in all 22 states where the birth rate levelled off or declined in 2008, economic conditions had "begun to deteriorate within the two previous years, when many potential parents were deciding... to have a child."
The birth rate decline was sharper for second and third children -- around six percent -- than for the first child, which was down by three percent, the NCHS study showed.