Planned Parenthood announced Tuesday it would no longer accept payments from companies that use tissue left over from abortions for research, bending to pressure in the wake of undercover videos targeting the group.

In a letter to the director of the National Institutes of Health, Planned Parenthood President Cecile Richards said the payments had become fodder for antiabortion activists. While the organization will continue to donate the tissue, its affiliates will no longer be permitted to recoup any costs from providing those donations, she said.

“Our decision is first and foremost about preserving the ability of our patients to donate tissue, and to expose our opponents’ false charges about this limited but important work,” Richards wrote.

The letter comes three months after a little-known antiabortion group called the Center for Medical Progress began releasing undercover videos purporting to show that Planned Parenthood profits by selling to research companies the body parts of aborted fetuses, which is illegal under federal law. The videos have dinged the reputation of the century-old women’s health nonprofit and triggered several state and congressional investigations.

Planned Parenthood officials have repeatedly denied wrongdoing, saying that only a handful of clinics supply tissue to researchers and that those programs are provided on a voluntary basis for women. And they have insisted that the clinics recoup only the costs they incur, which is permitted under federal law.

Only two Planned Parenthood affiliates — one in Washington state, and one in California — have active fetal tissue donation programs, officials said. The one in Washington does not take reimbursements, and until the policy change, the one in California received $60 per specimen, officials have said.

Dawn Laguens, executive vice president of Planned Parenthood, said in an interview that the decision to stop accepting any reimbursements for donated fetal tissue was “relatively easy, given that this was a small number of affiliates who have been able to do this and a small amount of money.”

Antiabortion activists contend that the $60-per-specimen charge exceeds the cost of facilitating the tissue donation. And they dismissed Planned Parenthood’s decision Tuesday as an insignificant gesture amid a host of other unethical and illegal practices they allege against the nonprofit.

“Today’s letter by [Cecile Richards] doesn’t negate the fact [Planned Parenthood] is breaking the law. This is just another deflection,” Lila Rose, president of the antiabortion group Live Action, tweeted Tuesday afternoon.

In an indication that the decision diffuses at least some of the controversy around the organization, Rep. Jason Chaffetz (R-Utah), chairman of the House Oversight committee, said in a statement that the announcement was “a good, tangible result of the collective efforts of the House in investigating Planned Parenthood. It is helpful in taking away some questions surrounding their transactions involving fetal tissue.”

Still, he said, “Significant questions still remain about Planned Parenthood’s finances.”

In the three-page letter to National Institutes of Health director Francis S. Collins, Richards reiterated Planned Parenthood’s position that it did nothing wrong, and she said the laws governing fetal tissue donation are adequate. But the allegations have provided a “smokescreen” for antiabortion activists to push laws curbing access to the procedure, prompting the organization to change its policy, Richards said.

Richards also reiterated her request for the National Institutes of Health to review policies related to fetal tissue donation.