For more than three decades, women in their late 20s had the highest birth rates, but that changed last year, according to preliminary data released Wednesday by the Centers for Disease Control and Prevention.

The birth rate for women ages 30 to 34 was about 103 per 100,000; the rate for women ages 25 to 29 was 102 per 100,000. The CDC did not release the actual numbers of deliveries for each age group.

It’s becoming more common to see older parents with kids in elementary or high school, said Bill Albert of the National Campaign to Prevent Teen and Unplanned Pregnancy.

Meanwhile, more teens are growing up with fewer of their peers getting pregnant, he said.