For the first time in eight years, Americans consider themselves more pro-choice than pro-life.

New Gallup polling shows that 50 percent of Americans identify with the "pro-choice" label. Forty-four percent identify as "pro-life."

Much of the shift looks to be happening among middle-age Americans. Support for abortion rights among people between the ages of 35 and 55 grew from 40 percent in 2012 to 52 percent this year.

The shift in favor of abortion rights has happened at a time when states have increasingly restricted access to abortion. States passed 231 abortion restrictions between 2011 and 2014 — more than the prior three decades combined. And more generally, separate Gallup polling shows that Americans have become more permissive on social issues over the past 15 years or so, whether that's abortion rights or babies out of wedlock or divorce. "The broader liberal shift in Americans' ideology of late could mean the recent pro-choice expansion has some staying power," Gallup analysts write.

A big caveat: Lots of Americas don't identify with these labels at all

The Gallup poll only gives respondents two options: they can identify as "pro-life" or "pro-choice." The problem, separate polling shows, is that lots of Americans don't pick these labels at all when given the additional options of labeling themselves "both" or "neither."

Vox fielded a poll earlier this year with communications firm PerryUndem that asked respondents whether they identified as pro-life, pro-choice, both, or neither. We found that 39 percent of Americans chose one of the latter two options; the singular labels, they told us, didn't apply to them.

We also found that simple wording changes can significantly shift how people think about the legality of abortion. Our pollsters, Mike Perry and Tresa Undem, gave a different question to the two halves of our polling panel. They asked one half whether they agreed with the statement "Abortion should be legal in almost all cases." The other half got a different wording of a similar idea: "Women should have a legal right to safe and accessible abortion in almost all cases."

Twenty-eight percent of the public agreed with the first statement — and 37 percent with the second. That's a jump of 9 percentage points in who thinks abortion ought to be generally legal, just by highlighting the fact that a woman is involved in the situation.

Results like these are one reason not to read too much into the new Gallup numbers. The pro-life and pro-choice labels often fail to capture the actual nuances of Americans' views on abortion.