Consider the most recent statistics available from the National Center for Health Statistics, part of the CDC:
In 2013, 3,932,181 babies were born in the U.S. This was less than a 1% decrease from 2012.
The mean age for women having their first baby in 2013 was 26 compared to 2010 when it was 25.
U.S. birth rate is 12.4 per 1,000 population
The fertility rate is 62.5 births per 1000 women aged 15 to 44 years
Percentage of babies born with a low birthweight is 8%
Percentage of babies born to unmarried couples is 40.6%
The teen birth rate fell 10%, to 26.5 per 1,000 women aged 15 to 19.
In 2013, the birth rate for twins rose to a new high for the nation of 33.7 per 1,000 total births. This is up 2% from 2012.
The preterm birth rate (under 37 weeks) declined to 11.39% in 2013. This decrease is a steady drop, trending since 2006, for a total decline of 11%.
The cesarean delivery rate decreased to 32.7% of all U.S. births for 2013. This is the first rate change since 2010.