(CNN) In certain key states, likely women voters say they'll vote for Democrats in much larger numbers than previous elections. CNN has collected data of polls of races rated as a Toss Up or Lean in CNN race ratings in which incumbents are running, women are supporting the Democratic candidate more often than they did in the incumbents' race in 2012.

In Ohio, Democrat Sherrod Brown beat Republican Josh Mandel in 2012 by 51% to 45%. According to CNN exit polls that year, significantly more likely women voters (56%) supported Brown than men (48%).

The edge among women that propelled Brown to re-election in 2012, a presidential election year which also featured President Obama on the ballot, has only grown. Now, in an NBC/Marist poll conducted in late September among likely voters, 60% of likely women voters said they'll support Brown for a third term. Women's support of the Republican has shrunk, 42% of women who voted for Mandel in 2012, but only 31% of women in that recent NBC poll who said they'll vote for Jim Renacci in the upcoming midterm election.

Men's support of Brown has waned slightly, from 48% in 2012 to 44% now. They haven't moved significantly on the Republican candidate.

This could be a blip. The NBC poll has a margin of error of plus or minus 4 percentage points. So in polling parlance, we are 95% confident that Brown's actual support is somewhere between 55% and 65% of likely women voters. It could be right about where it was in 2012.

But Brown's lead among women in that Ohio poll is mirrored at the national level, where women say in "generic ballot" questions that they plan to vote for a Democratic candidate in much higher numbers than past elections. Sixty percent of likely women voters who said they'd support a Democrat in CNN'S most recent poll . In 2014, 51% of women backed the Democrats in the national House exit poll, in 2010 it was 48% and in 2006 it was 55%.

Other key state polls show likely women voters moving away from Republicans, as well. A CNN poll conducted by SSRS was released this week, showing Democratic challenger Jacky Rosen with a very slight lead over incumbent Republican Dean Heller. Again, this lead is within the margin of error.

Exit polls in 2012 suggested 48% of women voted for Democrat Shelley Berkeley when Heller defeated her in 2012. The CNN poll shows likely women voters who said they'll vote for Rosen at 52%. Women have dropped on Heller with 42% who said they voted for him in 2012 and 38% planning to in 2018.

Men, meanwhile, haven't moved significantly on either candidate. Their support for the Democrat or Heller have remained relatively stable since 2012.

mid-September Marquette poll showed Democrat Tammy Baldwin with the support of 52% of all voters in Wisconsin, almost the same share she won in 2012. However, exit polls in 2012 suggested she had 56% of women that year. This year the Marquette University poll shows her current support at 60% among likely women voters. On the other side, the Republican challenger has suffered a loss. In 2012, Tommy Thompson received 41% of the female vote, according to exit polls. Now, Republican Leah Vukmir saw only holds the support of 31% of women likely voters, according to the Marquette poll.

Men of Wisconsin also haven't moved much. In 2012, 46% of men supported Tammy Baldwin, with 43% in 2018.

The growth among likely women voters in all of these polls is within the margin of error, which is important to note. That they all show growth for the Democratic candidates among women suggests it is more than just statistical noise

But not all states follow this trend.

In Missouri, CNN's new poll shows 55% of likely women voters plan on voting for Democratic incumbent Claire McCaskill in her bid for a third term. In 2012 , McCaskill got 58% of the woman vote in Missouri. The dip, again, could be attributed to the margin of error. However, in 2012 she was running against Republican Rep. Todd Akin, who inflamed opposition even among fellow Republicans after with a very controversial and specious remark about rape victims not often becoming pregnant.

McCaskill's opponent this year, Josh Hawley, has had no similar misstep. However, he did oversee the controversial the investigation of Gov. Greitens, when he was accused of an affair resulting in felony charges, which may have caused some women to shy away from the current Senate candidate. In this specific state, men have moved definitively towards the Republican candidate. In 2012, Akin got the support of 43% of men, according to exit polls, compared to 51% of men who said they will vote for Hawley now.

Other races aren't so clear. Some, such as Indiana, have seen some discrepancies in recent polling. Fox News found incumbent Democrat Joe Donnelly had the support of only 40% of the vote among likely women voters while an NBC/Marist poll saw him with 50% of women.

Historically, fewer people vote during midterm elections like this one than in presidential elections like 2012. Democrats, especially, who tend to have more likely women voters in their ranks than Republicans, have found difficulty with voter turnout in non-Presidential years.