While teen birthrates decreased at the national and state levels between 1990 and 2000, the number of adolescents having babies in Madison increased by 36 percent.

According to data from the Wisconsin Bureau of Health Information, released by the city’s Health Department Tuesday, there were 271 births to teens aged 15-19, resulting in an overall birthrate of 29.2 births per 1000 females of that age range, compared to 1990’s rate of 21.5.

Kelly Lindgren, UW-Madison associate professor in the school of nursing, said there has been a stabilization of the teen birthrate nationwide and could offer no explanation for Madison’s increase.

She said no evidence of a change in the number of what experts call “high-risk teens” living in the area has been found, but suggested the demographics of teens living in Madison may account for the difference between the city and state overall rates.

“Off the top of my head, we’re urban,” Lindgren said. “The population [in the city] is growing, and the demographics are changing rapidly.”

Mary Bradley, of the Madison Health Department, could also offer no explanation for the increase in teen birthrates.

“We don’t know yet,” Bradley said. “There are a lot of possibilities.”

Bradley said the department would work with other organizations in the community that work with teens in an attempt to explain, and improve, the city’s teen birthrate.

“Whether there’s been an influx of high-risk teens, we just don’t know yet,” Bradley said. “We’re just at a point of getting the data out there right now, and we’ll go from there.”

Of the Madison statistics, the largest overall percentage increase was in the 15-17 age group, which saw a 70 percent increase from 1990 to 2000. The 18-19 age group showed a 21 percent increase.

The rates among white teens and black teens varied. While birthrates in white teens aged 15-17 increased by 133 percent, the teen birthrate in black females of the same age group increased only 25 percent.

Lindgren said this difference is explained by the larger number of births among black teens than among white teens.

“There’s more room for an increase in [the white teen birthrate],” Lindgren said. “The rate for blacks was much higher to begin with.”

In Wisconsin, the number of teen births in 2000 was 36 per 1000 female teens, compared to 1990’s higher number of 43 per 1000 female teens. The national statistic also saw a decrease, with 49 births per 1000 females in the United States in 2000 compared to 60 in 1990.