TUPELO, Miss. - American women face increasing legal obstacles to obtaining abortions as more states pass laws restricting access, some so stringent they approach a ban on the procedure, according to a report issued on Wednesday by the Center for Reproductive Rights.

The New York-based advocacy group cited nearly 40 laws enacted across 15 states this year having the potential to restrict women's access to reproductive health care, nearly 40 years after the US Supreme Court's decision in Roe v. Wade made the controversial procedure legal.

Among the measures are some the group claims seek to ban abortion by imposing rules so burdensome upon women and providers it is nearly impossible to comply.

Mississippi and Tennessee passed such measures this year. The Center for Reproductive Rights has challenged the constitutionality of Mississippi's new law, which requires abortion providers to be certified in obstetrics and gynecology and have hospital admitting privileges.

A federal judge ruled last week that Mississippi could enforce the law, but also allowed the state's sole abortion clinic to continue legally operating while it tries to comply. Should the law ultimately result in the clinic's closure, Mississippi would be the first US state without a single abortion facility.

"I think the constitutional protection for women's rights to choose is robust, but that isn't stopping state legislatures from introducing terrible legislation and, increasingly, passing it," said Jordan Goldberg, the center's state advocacy counsel who authored the report entitled "2012 At the Midpoint: The Assault Continues."

"I don't think it's a question of the right not existing anymore," Goldberg said. "It's that we will have to resort to the courts to protect it."

The report referred to 2012 as the "powerful aftershock" that followed what it called last year's "seismic" attack on reproductive rights. More than 60 laws passed in two dozen states in 2011 seeking to restrict access to women's health care, according to the report.

But abortion opponents said the laws cited by the Center for Reproductive Rights aim to protect women from a sometimes unscrupulous industry peddling substandard care.

Dispute over quality of care

Fly-by-night abortion providers and dangerous chemical procedures have forced states to pass the recent legislation, said Mary Spaulding Balch, director of the department of state legislation for the National Right to Life Committee, a grassroots group that works against abortion.

"You're talking about lower-level health care providers," Spaulding Balch said.

Particularly troubling is the emergence of "circuit rider" abortion providers who fly from state to state performing procedures and leaving as soon as they're done, offering no aid to patients suffering later complications, she said. Recent laws requiring abortion providers to have local hospital privileges are meant to curb such scenarios, Spaulding Balch said.

Mississippi's lone abortion clinic uses out-of-state physicians. But owner Diane Derzis said women aren't abandoned after the procedure and can reach a clinic staff member 24 hours a day in case of complications, which are rare, she said.

Derzis has said the state's new law exists only to close her clinic, which has struggled to get local admitting privileges for its doctors. Despite anti-abortion statements by top Mississippi officials at the time of the bill's passage, its sponsor, Republican state Representative Sam Mims, said it was meant to protect women.

Other states cited by the report for their "harmful" laws are Alabama, Arizona, Georgia, Kansas, Louisiana, New Hampshire, North Carolina, Oklahoma, South Carolina, South Dakota, Tennessee, Utah, Virginia and Wisconsin.

Goldberg attributed the recent rush of laws in part to the large number of conservative leaders elected during the wave of anti-government sentiment in 2010. But she predicted a slowdown.

"There have always been these attacks," she said. "We've seen a backlash this year against the hostility that came out last year. When people look at what legislatures are doing, they'll be upset and they'll voice their frustration."