By Gabriella Borter

(Reuters) - Florida's Republican-led House of Representatives on Thursday gave final approval to a six-week abortion ban, setting the stage for abortion access to be drastically curtailed in the state and across the South -- and Gov. Ron DeSantis quietly signed the bill late on Thursday night.

Lawmakers in the Florida House approved the ban on abortions after six weeks of pregnancy in a 70-40 vote. The bill passed the state Senate by a vote of 26-13 on April 3. The legislation makes exceptions for abortions in cases of rape, incest and when the mother's life or health are at serious risk.

The Republican governor signed the state's current 15-week ban into law last year and has said he supports further limits.

Backing more severe restrictions could carry political risks for DeSantis, who is expected to seek the Republican nomination for president in 2024.

Abortion has emerged as a potent political issue in the U.S. since the Supreme Court overturned Roe v. Wade last year, with polls showing that support for abortion rights helped Democrats outperform Republicans in November's midterm elections.

A Reuters/Ipsos poll completed on Wednesday found that about 50 percent of Americans strongly or somewhat oppose a national six-week abortion ban, including 44 percent of Republicans. The same poll showed that 43 percent of Republicans said they were less likely to vote for a politician who supports limiting access to abortion.

"The ban flies in the face of fundamental freedoms and is out of step with the views of the vast majority of the people of Florida and of all the United States," White House press secretary Karine Jean-Pierre said in a statement.

Debate over the Florida measure lasted several hours on Thursday. Republican supporters of the bill said the law safeguarded women's health by making exceptions for dangerous pregnancies, and insisted doctors should not hesitate to perform life-saving abortions as the law allows.

"We have the opportunity to lead the national debate about the importance of protecting life and giving every child the opportunity to be born," said Republican Rep. Jenna Persons-Mulicka, a sponsor of the bill.

Democrats said the bill would harm women and that Republicans were prioritizing their religious beliefs and political gain over the health of their constituents.

"We are propping up a political agenda on the backs of women and birthing people," said Democratic Rep. Michele Rayner-Goolsby.

The fate of the ban will depend on the outcome of a court challenge to the state's 15-week abortion ban, which abortion providers have argued violates the state constitutional right to privacy.

If the Florida Supreme Court rules that the 15-week ban is constitutional, the six-week ban would take effect 30 days later.

Patients from across the U.S. Southeast have been traveling to Florida to end their pregnancies since the U.S. Supreme Court gutted federal abortion rights. Most other states in the region have already banned the procedure at early stages of pregnancy.

"It will turn Florida from one of the Southeast’s last access points for abortion to one that severely limits care," Alexandra Mandado, president and CEO of Planned Parenthood of South, East and North Florida, said of the ban.

(Reporting by Gabriella Borter in Washington; Editing by Colleen Jenkins and Matthew Lewis)