Since early last year, Planned Parenthood has been under siege. Republicans in the House attempted to end federal funding for the family planning group; legislators around the country cut funds. Abortion restrictions increased. In the Republican presidential primaries, Mitt Romney promised to defund the group. 

But in the face of increased opposition, Planned Parenthood found newly intense supporters. And the organization succeeded in widening the debate to include not just abortion but cancer screenings and contraceptives. In last week's election, results and exit polls suggest, the group won. 

In the Sunlight Foundation's rundown of outside groups and their success in last week's election, two groups stand out as getting a near perfect "return on investment" -- Planned Parenthood Votes and Planned Parenthood Action Fund, the super PAC and nonprofit arms of the family planning organization. 

Women Vote!, the super PAC arm of EMILY's List, had a solid 80 percent return on investment, meaning 80 percent of the money they spent went to winning candidates or against losing candidates. The group backs only pro-abortion rights Democratic women. 

Combined, the two Planned Parenthood advocacy groups say they spent $15 million on ads, phone calls, events, mail and door-to-door canvassing. In 2008, their campaign spending was about $4 million total. 

In large part, Planned Parenthood's success is due to President Obama's victory. Most of the groups' money went towards boosting Obama or attacking Romney. Eighty-seven percent of funds spent by Planned Parenthood Action Fund and 80 percent of spending by Planned Parenthood Votes went toward the presidential race, according to the Sunlight Foundation tallies. 

But the group also won six out of seven Senate races, three governor's races and five out of 10 House races. 

The organization held focus groups with undecided female voters in May and June that helped hone their message.

"We also did a set of targeting and modeling that was much more robust than we had ever done before," said Planned Parenthood Action Fund Executive Vice President Dawn Laguens. The group analyzed voters' positions not just on abortion but on birth control coverage and Planned Parenthood when deciding who to target and how. "We had an exceptionally on-target set of targets across the country and concentrated our resources very carefully," she said.

Women Vote! spent very little money on the presidential race; the group won 9 out of 10 Senate races it targeted, 18 out of 24 House races, and its only gubernatorial race. 

Ad data shows that abortion and women's health issues also played a far more prominent role in this race compared to 2008. 

In the presidential race, according to CMAG, over $37 million was spent on ads mentioning abortion. Of that, $29 million was spent by Democratic groups; $8 million was spent by Republicans. In 2008, only $8 million total was spent on abortion-related ads. Put another way, Democratic organizations spent 10 times as much on ads mention women's health in 2012 vs. 2008.

In Senate races, spending on ads related to women's health went up 88 percent, with Democrats running 1.5 times as many ads; in House races it went up 120 percent, with Democrats running three times as many ads.  

Network exit polls show an electorate that thinks abortion should be legal by a 59 to 36 percent margin. In Missouri, a Republican-leaning state where Sen. Claire McCaskill (D) easily defeated Rep. Todd Akin (R), 53 percent of the electorate said they believed abortion should be legal all or most of the time. In Ohio it was 55 percent, in Virginia 63 percent, and in New Hampshire 72 percent. 

In Montana, Sen. Jon Tester (D) credits the Planned Parenthood advocacy groups' work with helping him beat Rep. Denny Rehberg (R).

"Planned Parenthood understood the importance of Montana's race because women's rights were at stake, and they knew winning was going to take hard work and connecting directly with Montanans," he said in a statement. 

Marjorie Dannenfelser, president of the anti-abortion Susan B. Anthony's List, says her side needs to work on nominating "candidates that understand how to compassionately discuss the issue and go on the offensive rather than staying on the defensive." Too many conservatives, she said, instead seem to think that "if you just don't speak of it it won't come up. That's a recipe for a disaster." 

As for whether Planned Parenthood groups will play as big a role in future elections, Laguens says "it depends on the response of the Republican party to the election results."