In Oklahoma, half of its women legislators aren’t running for re-election this year because they're term-limited out. That rate may seem high, but in a state that ranks 49th for the percentage of women currently serving in the state legislature, it doesn’t take a lot to get there.

“Our numbers to begin with are very low,” said Cindy Simon Rosenthal, director of Oklahoma University’s Carl Albert Congressional Research and Studies Center. “This is a major turnover of women in the legislature.”

In total, eight women are leaving -- seven because their terms are up and one because she is running for another office and would vacate her seat if successful.

When term limits were implemented in the early 1990s, the policy was billed, among other things, as a way to get more women elected to the legislature. The idea was that term limits would periodically force open races, where women candidates have historically fared better.

But in the early 2000s, it became clear that term limits were not the panacea for increasing women’s representation in politics. Since they were passed in Oklahoma and a number of other states in the 1990s, the level of female representation in state legislatures has stayed at roughly 25 percent.