The birth rate of babies in the Badger state has been on the decline due to what an expert at University of Wisconsin says has to do with changes in Wisconsin’s economy.

Claire Smith, spokesperson from the Department of Health Services said the number of babies born in Wisconsin declined for the sixth year in a row last year.

The department recorded 66,566 live births to residents of Wisconsin in 2013, 633 fewer than the previous year. The teen birth rate also declined, with a crude rate of 19.7 births per 1,000 females aged 15 to 19, compared to 21.9 births in 2012.

Smith said the department only records data, so they were not able to put these numbers into context.

David Egan-Robertson, an applied demographer with University of Wisconsin’s Applied Population Laboratory, said the decline in the overall birth rate was most likely due to the 2007 recession.

” … When you look back further in the time series of birth patterns, every time there’s a recession you see birth rates start to decline,” Egan-Robertson said.

Egan-Robertson said this “recessionary pattern” was also present in Wisconsin after recessions at the start of the millennium in the early 1990s, and even further back at the beginning of the 1980s.

This pattern is not specific to Wisconsin, Egan-Robertson said. Recessions have caused a decline in birth rates nationally, following trends very similar to those in Wisconsin.

Egan-Robertson said trends like this are known as “period effects” and reflect a change in the environment rather than a population itself, as opposed to a “cohort effect” which reflects a change in some characteristic of a population and is a longer-term trend.

“There has been discussion in some academic circles as to whether the current generation coming into their most fertile years might be a cohort effect of actually having a reduced number of births long-term,” Egan-Robertson said.

This theory is very tentative, however. Egan-Robertson said it is impossible to know if a cohort effect is present until data is collected from a few more years. It cannot be said with certainty that there is a change in some characteristic of the population unless there is data over a more significant period of time.

If the birth rate continues to decline, there could be something bigger going on than family planning related to the recession, Egan-Robertson said. But few have speculated what the cause of such a trend would be. For now, the 2007-08 recession is the most probable cause of the decline in births both nationally and in Wisconsin.

“The decline in teen birth has been a longer-term pattern and has been declining since is peak in 1990, both in Wisconsin and nationally,” Egan-Robertson said.

Egan-Robertson said, unlike the overall birth rate, the teen birth rate has more to do with societal changes than the recession. He said the teen birth rate can be attributed to heightened efforts to encourage contraceptive use among teens.

It is possible that the decrease of overall births could be accounted for by something similar to this, but “we’ll have to wait until more data is collected to know for sure,” Egan-Robertson said.