CLEVELAND, Ohio — A federal judge blocked the state of Ohio’s so-called “heartbeat” law from going into effect, delaying authorities in this state from enforcing what would be one of the most restrictive abortion measures.

Senior U.S. District Judge Michael Barrett issued a 12-page order Wednesday granting a preliminary injunction, temporarily preventing the state from enforcing the law.

“This Court concludes that (the law) places an ‘undue burden’ on a woman’s right to choose a pre-viability abortion, and, under Casey, Plaintiffs are certain to succeed on the merits of their claim,” Barrett wrote, referencing the 1992 U.S. Supreme Court ruling Planned Parenthood v. Casey that said states cannot place undue burdens on women seeking an abortion.

Barrett, whose courtroom is in Cincinnati, said Wednesday’s ruling is based on current Supreme Court precedent. He wrote that the law will be blocked until he issues an order otherwise. The law was supposed to take effect next week.

(You can read the full ruling here or at the bottom of this story.)

The ruling is a blow, but far from a defeat, for proponents of the measure, which bars an abortion when doctors can detect a fetal heartbeat. Abortion opponents expected a legal battle over the law.

Senate Bill 23 was designed to punish doctors and others who perform abortions either after they detect a heartbeat or if they fail to perform an abdominal or transvaginal ultrasound to check for one. If convicted, an offender would face a fifth-degree felony, punishable by up to a year in jail and a $2,500 criminal fine.

The law includes exceptions for when the mother’s health or life are put at risk, but not for cases of rape or incest.

Fetal heartbeats can be detected as early as six weeks, before many women know they are pregnant. Ninety percent of Ohio abortions are performed at or after six weeks, Elizabeth Watson, staff attorney from the American Civil Liberties Union’s Reproductive Freedom Project, said at a news conference announcing the suit challenging the law. Planned Parenthood and Preterm-Cleveland were among the plaintiffs in the suit.

Gov. Mike DeWine signed the bill in April, giving his approval to a measure that his predecessor John Kasich vetoed. While Republican lawmakers in Columbus have passed other measures to curb abortion access in recent years, the “heartbeat” law is widely considered to be the most restrictive.

Other states have passed similar measures in recent months, including Georgia and Mississippi. None have gone into effect.

Barrett is a Republican appointee who issued several rulings in recent years that have lifted restrictions on abortion providers, even if only temporarily.

He wrote in Wednesday’s order that he is required to determine whether restrictions will present a substantial obstacle for a large fraction of women seeking an abortion. The “heartbeat” law, he wrote, "... will have the effect of preventing nearly all abortions in Ohio.

"One could characterize the obstacle Ohio women will face as not merely ‘substantial,’ but, rather, ‘insurmountable,’” Barrett wrote.

The judge said the state conceded that the plaintiffs have a likelihood of prevailing in their case based on current Supreme Court precedent that says abortion restrictions cannot be placed before a fetus is viable. However, attorneys for the state argued that the “viability” standard is flawed because of ongoing advancement in medical technology.

The state’s arguments are in line with those of abortion opponents, who have mused publicly about their hope that the conservative-leaning U.S. Supreme Court will ultimately overturn the seminal 1973 Roe v. Wade ruling and other cases that have given women abortion rights, and used the viability standard.

Barrett noted it too, though said it wasn’t for him to decide.

“To the extent that the State of Ohio ‘is making a deliberate effort to overturn Roe [v.Wade] and established constitutional precedent,’ … those arguments must be made to a higher court,” Barrett wrote.

A news release from the ACLU of Ohio, which included statements from Planned Parenthood and Preterm, praised the ruling.

“Today’s ruling keeps abortion legal for all Ohioans, but we know the fight does not stop there," Chrisse France, executive director of Preterm-Cleveland, said. “Ohioans deserve access to abortion that is safe, affordable, and without shame or judgment.”

Ohio Attorney General Dave Yost said Barrett’s ruling was expected.

“Casey’s elastic legal standard is ripe for review. This office will fulfill its duty to defend the laws passed by the elected representatives in the General Assembly,” Yost said in a statement.

Ohio Right to Life President Mike Gonidakis said in a news release that the ruling was disappointing but not surprising.

“The Heartbeat Bill has the potential to be the vehicle that overturns Roe v. Wade," Gonidakis said. "We know that this temporary restraining order is just a step in the process to finally seeing Roe reconsidered.”

NARAL Pro-Choice Ohio Deputy Director Jaime Miracle said in a statement that “the most important thing that Ohioans need to know is that abortion access is available in Ohio. When a person has decided to have an abortion, they should be able to access that care safely, affordably, in their community, with support and respect, not shame or pressure.”