The number and incidence of abortions in the U.S. fell in 2011 to the lowest point since the 1970s, news that is likely to be pored over by both sides to support their future campaigns. Louise Radnofsky reports on Lunch Break. Photo: Getty Images.

The number and incidence of abortions in the U.S. fell in 2011 to the lowest point since the 1970s, a new survey of American providers has found.

Some 1.06 million abortions were performed in 2011, down from 1.21 million in 2008, according to data collected by the Guttmacher Institute, an organization that supports abortion rights but produces data cited by both sides of the abortion debate. Those figures represent a continued decrease from higher numbers of the 1980s and 1990s to bring the total to its lowest point since 1975.

The ratio of the procedure also declined, to 21 per 100 pregnancies, from 23 per 100 in 2008, the last year for which research had been released.

The data, gathered during a wave of state-level legislation that placed new restrictions on abortion, is likely to be pored over by both sides to support future campaigns.

It also shows that the number of abortion providers remained stable, but that the proportion of procedures that were drug-induced—rather than with a surgical procedure—rose to comprise almost a quarter of all of those conducted outside of hospitals. The survey found that around 23% of abortions performed outside of hospitals in 2011 were induced using the drug mifepristone.

Drug-induced abortion has become a significant procedure in the past decade and opponents of abortion have increasingly focused their attention on it. The Supreme Court in November declined to take up a review of an Oklahoma law restricting drug-induced abortions.

The study is one of only a few large-scale efforts to quantify the number and location of abortions performed each year, and draws on the institute's ability to persuade a significant number of providers to respond to the survey. Antiabortion activists have pointed to the patchiness of state reporting requirements, and called for a more formal, mandatory reporting system.

States across the country passed 44 laws between 2008 and 2010 that tightened regulation of abortion, and another 62 laws in 2011, though many of those laws were not implemented immediately after their passage. The Guttmacher researchers said there were 1,720 U.S. abortion providers in 2011, a total that was only slightly less than the number in 2008, 1,793.

The researchers said the decline in abortion rates was relatively uniform across the country, rather than being connected to states where new laws were enacted, adding the change was possibly linked to declines in the rates of unintended pregnancy, which could be attributed to improvements in contraception use.

"We found no evidence that new abortion restrictions affected abortion incidence or services at the national level during the study period," the authors wrote, adding that "regardless of any measurable impact on incidence or services, increased regulation of abortion contributes to the stigmatization."

Some groups opposed to abortion criticized what they saw as a suggestion in the study that the state legislation they have promoted hasn't had an impact.

"The truth is that these common-sense limits on abortion protect women and their unborn children from abortion industry abuses," said Charmaine Yoest, president of Americans United for Life, in a statement.

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