South Carolina Governor Nikki Haley on Wednesday signed into law a bill banning most abortions after 19 weeks of pregnancy unless the mother's life is at risk, a spokesperson told Reuters on Wednesday.

The South Carolina legislature passed the bill last week, the 17th U.S. state to approve such a ban.

A signing ceremony will take place on a date to be announced later, said Haley spokesperson Chaney Adams.

The act, proposed last year in South Carolina's Republican-controlled legislature, passed after it was stripped of exceptions for pregnancies that result from rape of incest.

Sixteen other states have passed similar laws as conservatives have chipped away at the U.S. Supreme Court's landmark 1973 Roe v. Wade decision to legalize abortion. Courts have overturned the bans in three states.

"I believe that life begins at conception and every step we can take to get back to that point is important," the bill's sponsor, Republican Representative Wendy Nanney, told Reuters. "In my view and many others', it's inhumane to subject that baby to pain at 20 weeks."

Critics have said the name of the Pain Capable Unborn Child Protection Act goes against medical evidence showing that a fetus at 20 weeks cannot feel pain.

"This is a dangerous bill for South Carolina women ..., made even more extreme by removing exceptions for victims of rape and incest," Alyssa Miller, South Carolina director of public affairs for Planned Parenthood South Atlantic, said in a statement.

The law allows abortions at the 20-week mark if the pregnancy endangers a mother's life. It also includes a second exception if severe fatal abnormalities will mean the fetus would definitely die at full-term birth.

"The reality is that abortion later in pregnancy is extremely rare and often takes place in complex and difficult situations where a woman and her doctor need every medical option available," Miller said.