The mean age at birth for all mothers increased from 28.7 in 2016 to 29.6 in 2023, according to the report. For first births, the average age rose from 26.6 years to 27.5 during this period.

The percentage of first births rose by 12.6 percent in women aged 30-34 and by 25 percent for women aged 35 and above.

In contrast, the percentage of first births among women aged 20-24 declined by 9 percent, and for those younger than 20 by 26 percent.

"Higher maternal age is linked to smaller family size on average and may carry different health risks and benefits compared with younger maternal age," the CDC said.

"The findings of this analysis suggest that U.S. women may be continuing to delay motherhood," it added. "Motherhood is increasingly delayed across most races and Hispanic-origin groups."

Asian mothers saw the largest increase in average age at first birth of 1.4 years. Native Hawaiian or Other Pacific Islander mothers had the smallest increase at 0.4 years.

A 2023 study published by PubMed Central showed that women were delaying childbearing due to factors such as education, participation in the labor market, and shifting personal preferences.

"Access to safe, efficient, and reversible pregnancy prevention methods" has also contributed to delayed childbearing in women, it said.

While speaking to reporters on April 22, President Donald Trump indicated he was willing to consider financial bonuses to boost birth rates in the United States.

Earlier this month, the administration announced it was ending a Biden-era guidance that directed hospitals to provide women with emergency abortion services.

The guidance was issued in 2022 after the Supreme Court overturned Roe v. Wade and returned decisions regarding abortions to the states.

Earlier this year, Vice President JD Vance said he wanted more babies born in the United States. The American society has "failed to recognize the obligation that one generation has to another as a core part of living in a society," he said.