Planned Parenthood president Cecile Richards, joined by House Minority Leader Nancy Pelosi of Calif., left, and Rep. Diana DeGette, D-Colo., right, and others, speaks during a news conference discussing women's health care, Thursday, Jan. 5, 2017, on Capitol Hill in Washington. (Zach Gibson/AP)

A fierce battle over the future of reproductive rights is now underway in Washington as congressional Republicans made the first move last week to slash funding for Planned Parenthood.

In starting to roll back the Affordable Care Act, the GOP is also planning to target the country’s largest women’s health-care provider. Planned Parenthood could lose millions in dollars of reimbursements from Medicaid and other funding as soon as this spring, if the repeal effort advances.

President-elect Donald Trump’s pick to head the Department of Health and Human Services, Rep. Tom Price (R-Ga.), is likely to be an ally — his ACA replacement bill prevents federal funds from going to health-care plans that cover abortions. A courtesy hearing on his nomination is to start Wednesday before the Senate Health, Education and Labor Committee.

Planned Parenthood has responded by organizing a massive public outreach campaign aimed at convincing Congress that voters support the nonprofit group. Two weeks ago, abortion rights advocates attempted to deliver more than 70,000 petitions to the office of House Speaker Paul D. Ryan (R-Wis.).

Actor Wilson Cruz speaks to supporters of Planned Parenthood at the Capitol Pink Out Day 2017 on Tuesday, Jan. 17, 2017, in Sacramento, Calif. Proponents rallied against House Speaker Paul Ryan's budget bill which would halt federal funding for Planned Parenthood. (AP Photo/Rich Pedroncelli) (Rich Pedroncelli/AP)

Many of those activists worry that the Republican Congress — helped by Trump — will seize on blanket control of Washington to further restrict and ban some abortion procedures, or even seek to reverse Roe v. Wade, the 40-year-old Supreme Court decision that legalized the procedure.

“Right now we are trying to do everything possible to fight back against these attempts and talk to members of Congress,” Raegan McDonald-Mosley, Planned Parenthood’s chief medical officer, said in an interview. “We will continue to be around, but if we are unable to serve that million-plus people, our organization will certainly look different.”

Capitol Hill Republicans have given abortion rights supporters cause for alarm. They have long unsuccessfully targeted Planned Parenthood, arguing that no abortion provider should receive federal funding. Next week, they intend to vote on a measure to ban such funding with exceptions for rape, incest and the life of the mother.

Although previous GOP efforts to defund the group ended in vetoes by President Obama, Republicans are hopeful that Trump will support such language. Many Republicans were deeply disturbed by undercover video released last year that some viewed as showing Planned Parenthood officials talking about selling fetal tissue.

“We don’t want to effectively commit taxpayer money to an organization providing abortions,” Ryan said at a recent CNN town hall.

Democrats insist that federal law already prevents public money from paying for abortions and argue that Planned Parenthood provides broad health services — from birth control to screening for sexually transmitted diseases to mammograms and other preventive care.

Democrats acknowledge that with no check from the president, congressional Republicans may succeed in using special budget procedures to slash funding for the group by as much as 50 percent.

“This has been an easy vote for a lot of Republicans to say they’re going to take a political vote. But this time it’s real bullets,” said Sen. Patty Murray (D-Wash.), the No. 3 Senate Democrat.

“They will have people in their home states, in their communities, who don’t get access,” she said in a recent interview. “They will see Planned Parenthood clinics cut down and the world will go very dark for a lot of people.”

Planned Parenthood estimates that half of the 2.5 million patients who visit its clinics each year are insured through Medicaid. Of those patients, about 10 percent are men, and 75 percent meet the federal definition of low or moderate income, McDonald-Mosley said.

Abortion rights supporters worry attacks on Planned Parenthood could be the first volley in a broader strategy. Unlike the ACA, which Ryan and other leaders have said will remain while a replacement plan is phased in, a measure targeting Planned Parenthood is expected to take effect as soon as the repeal bill passes — potentially ending access to services within months for more than a million women.

Some moderate Republicans worry that the push could make it look as though the GOP is unfairly and aggressively singling out one health group that mainly serves women.

“This is saying that Planned Parenthood is going to be treated differently from other health-care providers when it comes to Medicaid,” said Sen. Susan Collins (R-Maine). “I think that’s wrong.”

Collins and Sen. Lisa Murkowski (R-Alaska) say they would consider opposing any bill that cuts funding for the group. But they declined to commit to voting against the ACA repeal, saying it has not been written.

“That is certainly something I would have to take into consideration,” Murkowski said, referring to voting against the entire repeal bill to protect Planned Parenthood.

House Republicans plan to base their attempt to cut the group’s funding on a 2015 measure to block Planned Parenthood from receiving Medicaid reimbursements for a year. Obama vetoed that measure when it passed as part of a broader attempt to repeal the ACA. But now, Trump is eager to repeal and replace Obamacare.

Trump has praised Planned Parenthood for doing good work.

“I would look at the good aspects of it, and I would also look because I’m sure they do some things properly and good for women,” Trump said on CNN in August. “The abortion aspect of Planned Parenthood should absolutely not be funded.”

Senate Minority Leader Charles E. Schumer (D-N.Y.) said that pushing forward on plans to cut Medicaid dollars for the organization will only make it harder for Ryan to make sure ACA repeal legislation has enough Senate votes.

Public opinion on abortions has been mixed in recent years, but a majority of voters have consistently backed funding for Planned Parenthood.

Last year, a poll conducted by Politico and Harvard University found that 58 percent of voters thought the organization should receive federal funding, including 48 percent of Trump voters.

Republicans already tested the waters on Planned Parenthood in the 2015 bill that served as a dress rehearsal for the ACA fight. At the time, Democrats asked the Senate parliamentarian to rule that a section clearly aimed at ending the group’s funding couldn’t be included in the final bill.

The parliamentarian ultimately decided that section was allowed under Senate rules. Democrats plan to renew their fight this year.

Republican leaders are relying on a special quirk in Senate rules to repeal the ACA and without the threat of a blockade by Senate Democrats. That quirk could allow the Planned Parenthood defunding language to be passed with a simply majority, or 51 votes — and the GOP has 52 senators.

But those rules are limited to measures related to taxes and spending and those with an impact on the long-term debt and deficit.

Democrats contend there is a serious long-term cost to denying low-income women access to preventive services such as birth control.

The 2015 language was carefully written so as not to target Planned Parenthood by name. Instead, Democratic aides said, the measure aimed to deny Medicaid reimbursements and other funds to essential community nonprofits that provide abortions — a definition that applies almost exclusively to Planned Parenthood.

The funding cuts were also limited to one year. Republicans argued for pausing payments to Planned Parenthood while Congress investigated accusations that some clinics mishandled the tissue of aborted fetuses.

Democrats, however, said the one-year limit had far more to do with an independent estimate that cutting birth-control services would eventually cost the government $130 million over 10 years. The costs would come from an increase in the number of unplanned pregnancies and children who would eventually need coverage through Medicaid.

Ryan has said other community health groups will help fill any gap left by Planned Parnthood. But the group maintains it is the only provider for many women across the country.

Murkowski said in an interview that Planned Parenthood is the only entity in Alaska that screens for sexually transmitted diseases for low-income individuals — including for men.

“I respect the fact that there are those who feel very strongly about not having federal dollars directed to abortion services, and I have said that that is something I am consistent and in alignment with,” Murkowski said. “But I also recognize that Planned Parenthood does so much more than abortions.”

Sankhya Somashekhar contributed to this report.