Consider the most recent statistics available from the National Center for Health Statistics, part of the CDC:
In 2010, 3,999,386 babies were born in the U.S. This was a 3 percent drop from 2009.
The mean age for women having their first baby in 2010 was 25.
The first-birth rate for women age 30 to 34 and 40 to 44 is on the rise.
The birth rate for teenagers ages 15 to 19 years decreased by 10 percent in 2010, to 34.2 per 1000. This is the lowest reported level in the United States in seven decades.
In 2010, the twin birth rate decreased to 33.1 twin births per 1,000 women.
The preterm birth rate (less than 37 weeks in the womb) was 11.99 percent in 2010.
Cesarean deliveries accounted for 32.8 percent of all births in 2010.