The change “is something that we have been talking about for several years,” said Cecile Richards, the president of Planned Parenthood Federation of America. “I just think the ‘pro-choice’ language doesn’t really resonate particularly with a lot of young women voters. We’re really trying to focus on, what are the real things you’re going to lose? Sometimes that’s rights. Sometimes that’s economic or access to health care for you or for your kids.”

Pro-choice became commonplace after the 1973 Roe ruling, to counter the pro-life label of the anti-abortion movement. The description was seen as having broader appeal than “pro-abortion,” since it fit those who were personally against abortion but opposed any government control over women’s health decisions.

“ ‘Choice’ has been extraordinarily successful as a frame for the abortion-rights side because a lot of Americans may not like the idea of abortion but they definitely agree with the idea of choice,” said Suzanne Staggenborg, a professor at the University of Pittsburgh who researches social movements. “And they agree that it should be a woman’s choice in consultation with her doctor.”

But by 2010 some abortion-rights activists began to sense in their outreach to young women, whose support was needed not only for the midterm elections but for the movement’s future as well, that the term pro-choice was virtually meaningless. That was confirmed by postelection polls and focus groups that women’s organizations and Democrats commissioned to understand what went wrong.

Among the findings, according to several people familiar with them: Many young women, when asked whether they were pro-choice or pro-life, said pro-life. Yet they supported the Roe ruling. Explaining the contradiction, Ms. Laguens said these self-described pro-life voters were “talking about their personal decision-making, for themselves, and not about what they want to push on others.”

But such results also showed the weakness of the pro-choice label, advocates and pollsters said. Planned Parenthood took the lead, conducting research on public attitudes throughout 2011 and then presenting the findings to allies in various meetings.

“It definitely was a bit destabilizing when we started,” Ms. Laguens said. When Planned Parenthood produced a YouTube video last year for supporters on the shift to a broader message, one member wrote online: “I’m pro-choice and I won’t be bullied into saying anything different. This is nothing but a retreat and a shame!”