By Gabriella Borter

(Reuters) -Idaho has become the latest Republican-led state to pass a “fetal heartbeat” law, prohibiting abortions after five or six weeks of pregnancy except in medical emergencies or in cases of rape or incest.

The law, signed by Republican Governor Brad Little on Tuesday, follows a wave of similar legislation passed by states aiming to prompt a review of the 1973 U.S. Supreme Court ruling Roe v. Wade, which guarantees a woman’s constitutional right to an abortion.

Also on Tuesday, Arizona passed a law banning abortions performed strictly on the basis of genetic disorders detected in the fetus, such as Down syndrome or cystic fibrosis, unless the condition is considered lethal.

“We should never relent in our efforts to protect the lives of the preborn,” Little said in a statement.

The “fetal heartbeat” law bans abortion once a fetal heartbeat is detected, often at six weeks. That could be before a woman realizes she is pregnant.

Idaho’s law states that it will only go into effect 30 days after any U.S. appeals court upholds another fetal heartbeat abortion ban, as several states are in legal battles to have their laws enacted.

“This legislation changes nothing,” abortion rights group Planned Parenthood Votes Northwest and Hawaii said in a statement posted to Facebook on Tuesday.

“What it really does is simply set Idaho up for a lawsuit if a similar ban in another federal court upholds their unconstitutional legislation – and there is nothing that indicates that would ever happen. But even if it does, we will launch a lawsuit immediately to stop it,” the statement said.

Abortion is one of the most divisive issues in the United States, with opponents citing religious belief to declare it immoral, and proponents declaring it a women’s health and privacy issue, among other arguments.

Several Republican-led states have passed restrictions on abortions at around six weeks and most are still tied up in the courts. A law passed in Iowa in 2018 was overturned by a state judge in 2019.

“It is undisputed that such cardiac activity is detectable well in advance of the fetus becoming viable,” District Court Judge Michael Huppert wrote in his decision.

A fetus that is viable outside the womb, usually at 24 weeks, is widely considered the threshold in the United States to prohibit abortion.

(Reporting by Gabriella BorterEditing by Bill Berkrot)