(CNN) -- The president of an influential abortion rights political advocacy group will step down after the upcoming national election, her organization announced Thursday.
Nancy Keenan, who has led the National Abortion Rights Action League Pro-Choice America since December 2004, chose "not to renew her contract," the group said in a news release.
"Thanks to all of you who have supported me these past 8 years at @NARAL," Keenan wrote Thursday on her Twitter account. "I look forward to fighting with you through 2012!"
Members of the league's board of directors lauded Keenan in announcing her departure.
"Nancy inspired Americans, from lawmakers to everyday citizens, to proudly proclaim their pro-choice views and act on these values," said Janet Denlinger, the board's chairwoman.
"Nancy directed efforts that reshaped the debate over reproductive rights, produced tremendous electoral wins for choice, and defeated attacks from anti-choice opponents. As a result, we are a stronger organization positioned to lead the fight for reproductive rights now and into the future."
According to her official biography, Keenan was one of five siblings growing up in an Irish-Catholic family in the copper-smelting town of Anaconda, Montana.
She taught children with disabilities in her hometown before becoming a Montana state legislator and state superintendent of public instruction.
Under her leadership, the league claimed that 44 more abortion rights people earned seats in the U.S. House of Representatives and eight more in the U.S. Senate in the 2006 and 2008 election cycles. This effort suffered "significant setbacks" in 2010 against what the group called "an extreme anti-choice agenda unfolding in Washington."
Keenan will continue with the abortion rights group, which is based in Washington and oversees 20 state affiliates, through January 2013. In that time, she will "focus on helping pro-choice candidates win elections."
In the meantime, a search committee has been formed made up of members from across the country to select her successor.
"We have built an innovative initiative to engage and recruit even more members of the Millennial Generation to the pro-choice cause," Keenan said. "We did this by listening and learning from younger people about their experiences and ideas for protecting choice in the next 40 years and beyond."