(Adds comment from legal analyst)
By Alex Dobuzinskis
March 20 (Reuters) - A U.S. federal judge on Tuesday temporarily blocked a Mississippi law that enacted the tightest restrictions on abortion in the United States, in a ruling handed down a day after the governor signed the measure.
The Mississippi law would prohibit abortion after 15 weeks of gestation, with some exceptions. It went into effect immediately after Republican Governor Phil Bryant signed it on Monday. State law previously banned abortion at 20 weeks after conception, in line with limits in 17 other states.
The judge's ruling blocks the measure for 10 days, while he considers arguments on whether to stop the law from taking effect until the outcome of a full legal challenge.
"The Supreme Court says every woman has a constitutional right to 'personal privacy' regarding her body," U.S. District Court Judge Carlton Reeves in Jackson, Mississippi, said in a two-page ruling that quoted from the high court's 1973 Roe v. Wade ruling that legalized abortion.
The judge said a stay was justified because the Mississippi law's proposed 15-week limit is outside of the medical consensus about when fetus becomes vital, raising questions about whether it violates the U.S. Constitution.
Abortion rights groups say anti-abortion organizations could use the case to test limits on abortion all the way to the Supreme Court. The court in the past has struck down prohibitions on abortion before fetal viability, usually considered to be about 20 weeks of gestation.
The Jackson Women's Health Organization, the only clinic providing abortions in Mississippi, sued to block the measure on Monday.
"We will fight this unconstitutional ban and ensure that women can access legal and safe abortion care, no matter their zip code," the New York City-based Center for Reproductive Rights, which is representing the clinic in court, said in a statement on Twitter after the ruling.
If the case reaches the Supreme Court, it is unclear how it would decide on the 15-week ban. President Donald Trump's appointee, Justice Neil Gorsuch, is unlikely to be a deciding factor, said Jessica Mason Pieklo, a legal analyst at reproductive rights website Rewire.news.
"If the Supreme Court follows precedent, the Mississippi law should be struck down," Pieklo said by phone. "If the court is looking for an opportunity to revisit and potentially overturn Roe, then the Mississippi case may give them the vehicle to do so."
In 2016, the Supreme Court refused to uphold an Arkansas law that banned abortion after 12 weeks' gestation as well as a North Dakota six-week law.
The Mississippi governor called the judge's ruling on Tuesday disappointing.
"House Bill 1510 protects maternal health and will further our efforts to make Mississippi the safest place in America for an unborn child," Bryant said in a statement. "We are confident in its constitutionality and look forward to vigorously defending it."
The Mississippi law includes an exception in the case of severe fetal abnormality or a medical emergency.
(Reporting by Alex Dobuzinskis in Los Angeles; Editing by Cynthia Osterman)
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