The Washington Post reports: The U.S. birthrate plunged last year to a record low, with the decline being led by immigrant women hit hard by the recession, according to a study released Thursday by the Pew Research Center.

The overall birthrate decreased by 8 percent between 2007 and 2010, with a much bigger drop of 14 percent among foreign-born women. The overall birthrate is at its lowest since 1920, the earliest year with reliable records. The 2011 figures don’t have breakdowns for immigrants yet, but the preliminary findings indicate that they will follow the same trend.

The decline could have far-reaching implications for U.S. economic and social policy. A continuing decrease could challenge long-held assumptions that births to immigrants will help maintain the U.S. population and create the taxpaying workforce needed to support the aging baby-boom generation.

The U.S. birthrate — 63.2 births per 1,000 women of childbearing age — has fallen to a little more than half of its peak, which was in 1957. The rate among foreign-born women, who have tended to have bigger families, has also been declining in recent decades, although more slowly, according to the report.

But after 2007, as the worst recession in decades dried up jobs and economic prospects across the nation, the birthrate for immigrant women plunged. One of the most dramatic drops was among Mexican immigrants — 23 percent.