The higher birth rates at older ages during the baby boom largely reflected women having third, fourth, or higher-order births rather than first or second births.

Teen birth rates remained relatively low in the 1970s and 1980s, despite large increases in the proportion of teenagers who were sexually active. The teen birth rate edged up around 1990. But, by 2020 increases in contraceptive use and a leveling of the share of teens who were sexually active helped reduce the teen birth rate to 15.3—the lowest level ever recorded in the United States.

Education and income also play a significant role in fertility. In nearly every contemporary society, people who are more educated and have higher incomes have fewer children than those who are less educated and have lower incomes.

In 2017, U.S. women ages 25 and older with an advanced degree had an average of 1.80 children, compared with 2.25 children for women with a high school diploma and 2.70 children for women without a high school diploma.10

Why is the U.S. Birthrate Declining?