Recently released official U.S. birth data for 2020 showed that births have been falling almost continuously for more than a decade. For every 1,000 women of childbearing age (15 to 44), 55.8 of them gave birth in 2020, compared to 69.5 in 2007, a 20 percent decline. The “total fertility rate,” which is a measure constructed from these data to estimate the average total number of children a woman will ever have, fell from 2.12 in 2007 to 1.64 in 2020. It is now well below 2.1, the value considered to be “replacement fertility,” which is the rate needed for the population to replace itself without immigration.
https://www.brookings.edu/blog/up-front/2021/05/24/will-births-in-the-us-rebound-probably-not/
