Their challenge will come on the heels of a court victory in Idaho, where a less restrictive ban was overturned.
On Wednesday, the Republican-controlled state legislature in Arkansas overrode a veto by Gov. Mike Beebe, a Democrat, to enact the nation's strictest state-level abortion restriction. Under the new law, proposed as S.B. 134, abortions will be banned when women have been pregnant for 12 weeks and an abdominal ultrasound shows that the fetus has a heartbeat.
Abortion-rights groups quickly denounced the new law as an assault on reproductive rights.
"We are deeply disappointed that the Arkansas legislature voted to impose the most restrictive ban on safe and legal abortion in the country," Planned Parenthood President Cecile Richards said in a statement released to reporters on Wednesday, speaking through her group's political arm.
"The majority of Arkansans -- and the majority of Americans -- don't want politicians involved in a woman's personal medical decisions about her pregnancy," Richards said. "Governor Beebe rightfully vetoed this legislation and the legislature would have been wise to let the veto stand as this bill is clearly unconstitutional."
Abortion-rights groups claim that the law violates federal abortion policy, as laid out in the landmark Roe v. Wade Supreme Court case.
Under Roe v. Wade, states can ban abortion after a fetus reaches "viability" -- defined as the point when a fetus could survive outside its mother's womb. Viability is usually reached at 24 to 28 weeks.
In vetoing the bill on Monday, Gov. Beebe issued a statement that S.B.134 "blatantly contradicts the United States Constitution, as interpreted by the Supreme Court" because it would ban abortions "well before viability."
Anti-abortion activists, meanwhile, have praised the law.
"Unborn children jerk away from painful stimuli, their stress hormones increase, and they require anesthesia before any fetal surgery. With today's override of the governor's veto, Arkansas has become the eighth state to pass legislation protecting unborn children capable of feeling pain from the violence of abortion," Mary Spaulding Balch, director of state legislation for National Right to Life, said last week when the legislature first passed the bill.
The Center for Reproductive Rights announced that, along with the Arkansas American Civil Liberties Union, it would challenge the new law in federal court before it takes effect after the end of Arkansas's legislative session.
"We intend to make it equally clear that no one's constitutional rights are subject to revision by lawmakers intent on scoring political points, and that attempts such as this to turn back the clock on reproductive rights will not stand," Center for Reproductive Rights President and CEO Nancy Northrup said in a statement released Wednesday.
The new court case will follow a victory for abortion-rights advocates in Idaho, where a federal district judge overturned the state's 20-week abortion ban, finding that it violated the viability standard laid out in Roe v. Wade.
"Because it appears [the ban] was enacted with the specific purpose of placing an insurmountable obstacle in the path of women seeking an abortion after twenty weeks, but before the fetus has attained viability, the section imposing the categorical ban is unconstitutional," District Judge B. Lynn Winmill wrote in a decision on Wednesday.
Abortion opponents have succeeded in passing several state bans on abortions at 20 weeks or earlier since 2010. Since Nebraska passed a 20-week ban in 2010, nine other states have passed similar bans: Alabama, Arizona, Arkansas, Georgia, Indiana, Idaho, Kansas, Louisiana, and Oklahoma.