BISMARCK, N.D. -- The North Dakota Senate on Friday approved banning abortions as early as six weeks into a pregnancy, sending what would be the most-stringent abortion restrictions in the U.S. to the state's Republican governor for his signature.

The measure would ban most abortions if a fetal heartbeat can be detected, something that can happen as early as six weeks into a pregnancy. The House already approved the measure. Gov. Jack Dalrymple generally opposes abortion but has not said whether he will sign the bill into law.

It's one of several anti-abortion measures the state Legislature has weighed this session. The vote came with almost no debate in the Senate and after the same chamber approved another measure that would make North Dakota the first to ban abortions based on genetic defects such as Down syndrome.

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That measure would also ban abortion based on gender selection. The Guttmacher Institute, which tracks abortion laws throughout the country, says Pennsylvania, Arizona and Oklahoma already have such laws. 

Some supporters of the so-called fetal heartbeat measure have said they hope to send a message that North Dakota is anti-abortion and aims to challenge the U.S. Supreme Court's 1973 Roe v. Wade ruling that legalized abortion up until a fetus is considered viable, usually at 22 to 24 weeks.

Arkansas passed a 12-week ban earlier this month that prohibits most abortions when a fetal heartbeat can be detected using an abdominal ultrasound. That ban is scheduled to take effect 90 days after the Arkansas Legislature adjourns. 

A fetal heartbeat can generally be detected earlier in a pregnancy using a vaginal ultrasound, but Arkansas lawmakers balked at requiring women seeking abortions to have the more invasive imaging technique.

North Dakota's measure doesn't specify how a fetal heartbeat would be detected. Doctors performing an abortion after a heartbeat is detected could face a felony charge punishable by up to five years in prison and a $5,000 fine. Women having an abortion would not face charges.

A spokeswoman for the Guttmacher Institute, which tracks abortion laws across the country, said North Dakota's measures are the latest in a "tidal wave of abortion restrictions" in the U.S.

"We have seen efforts to ban abortion entirely and those attempts have failed," spokeswoman Elizabeth Nash said. "Now they're moving toward banning abortions as early as possible."

Abortion-rights advocates say the anti-abortion measures in the North Dakota Legislature are attempt to close the state's sole abortion clinic, in Fargo. They also say the so-called fetal heartbeat bill is a direct challenge to Roe v. Wade, and its supporters should expect a costly legal fight if it becomes law.

Republican Rep. Bette Grande, an ardent opponent of abortion from Fargo who introduced the fetal heartbeat bill, said fears about potential litigation should not prevent lawmakers from approving the measure.

"Whether this is challenged in court is entirely up to the abortion industry," Grande told lawmakers this week. "Given the lucrative nature of abortion, it is likely that any statute that reduces the number of customers will be challenged by the industry." 

Arizona lawmakers appear close to sending to Gov. Jan Brewer a tea party-backed bill that proponents say would stop a United Nations takeover conspiracy but that critics claim could end state and cities’ pollution-fighting efforts and even dismantle the state unemployment office.

A final legislative vote is expected Monday on a bill that would outlaw government support of any of the 27 principles contained in the 1992 United Nations Rio Declaration on Environment and Development, also sometimes referred to as Agenda 21.

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Senate Bill 1507 was passed by the state Senate last month and received an initial House affirmation Wednesday. It is sponsored by state Sen. Judy Burges, R-Sun City West, who also sponsored a state birther bill that Brewer vetoed last year.

"The bill is designed to protect the rights of Arizona citizens and prevent encroachment on those rights by international institutions," Burges told msnbc.com in an email. "We have three branches of government and when one branch preempts the process through executive orders, the balance of power is lost in the process. It is that simple -- no more, no less."

At a March 15 hearing on the bill, Burges said an executive order signed by then-President Bill Clinton in 1993 started the implementation of Agenda 21 after the Senate refused to pass a treaty ratifying it.

"Any way you want to describe it, Agenda 21 is a direct attack on the middle class and working poor" through "social engineering of our citizens" in "every aspect" of their lives," she told the hearing. 

But House Minority Leader Chad Campbell, D-Phoenix, has a different view.

“It’s the most poorly crafted bill in this state,” Campbell told msnbc.com. “It’s so broad and overreaching, we’re not sure what it could impact.”

Among the U.N. declaration’s non-binding principles are calls for sustainable development, environmental protection, eradicating poverty, eliminating unsustainable production and consumption patterns, economic growth and the participation of women in government decisions.

“We wouldn’t be able to use CFL light bulbs in state buildings because that would be considered energy efficiency,” Campbell said.

Campbell also said that the state’s Economic Security Department, which handles unemployment and welfare benefits, could be outlawed because it has to do with eradicating poverty.

Also, Arizona universities have sustainability programs that could be banned if the bill becomes law, Campbell warned.

Arizona State University has a School of Sustainability, Northern Arizona University offers a master's in sustainable communities, and the University of Arizona has an environment and sustainability portal.

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Brewer, who last spring vetoed Burges' bill to require presidential candidates to prove their U.S. citizenship, typically does not comment on legislation until it reaches her desk, her spokesperson told msnbc.com Thursday.

About the Rio declaration, SB1507 says “the United Nations has enlisted the support of numerous independent, shadow organizations to surreptitiously implement this agenda around the world.”

Rep. Terri Proud, R-Tucson, told supporters in an email that the U.N. declaration “will take away our rights as Americans by allowing the United Nations to mandate laws on our soil,” the AzCapitolTimes.com reported. “It’s very real and it is happening.”

The Times also reported that during House debate Wednesday, Rep. Jack Harper, R-Surprise, said the declaration is connected to the “occult” of sustainability.

"The tea party and conspiracy theorists run the state now, Campbell told msnbc.com.

See video from the March 15 House Judiciary committee meeting on SB1507 here.

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