The average age of moms giving birth in the U.S. continues to rise, hitting nearly 30 years old in 2023, according to a new report from the Centers for Disease Control and Prevention.

In the report, published Friday by the CDC’s National Center for Health Statistics, researchers found the average age of all mothers giving birth in the United States increased from 28.7 years old in 2016 to 29.6 in 2023. For new first-time moms, average age also increased, from 26.6 in 2016 to 27.5 in 2023. The data was taken from the National Vital Statistics System, which includes all birth records in the country. 

Dr. Jessica Shepherd, board-certified OB-GYN and chief medical officer at women’s health company Hers, told CBS News there are many contributing factors behind this shift, including changes in social expectations and values.

“Also, there has been an improvement in technology and innovation when we think of fertility, which allows (people to) prolong pregnancy and childbearing,” said Shepherd, who was not involved in the report. 

The cost of raising children is also going up, which could be another factor in people deciding to wait, said Jessica Holzer, an associate professor at the University of New Haven with a doctorate in health policy and bioethics. 

“(This) is likely creating pressure on families to wait for financial stability before conceiving and to time second, third and more pregnancies in light of affordability,” she said. 

The report also tracked a continuing decline in teen pregnancies, which have dropped from 11.8% of first births in 2016 to 8.7% in 2023.

Based on available data, Holzer said it’s unclear whether this is due to adolescents delaying sexual activity “or if the shift is more attributable to contraceptive practices among adolescents who are sexually active.”

“Either could be contributing to the changes demonstrated in this report and both have been targets for the CDC that have driven intervention programs in schools and communities for decades,” she added.

Shepherd said this decline could also be attributed to economic factors and to social media, which she said “drives more conversation” around pregnancy.