The Trump administration will block government scientists from acquiring new fetal tissue from abortions to use in medical research, a major victory for abortion opponents.

"Promoting the dignity of human life from conception to natural death is one of the very top priorities of President Trump’s administration," the Department of Health and Human Services said in a statement Wednesday that announced the change.

The decision comes after months of speculation, as well as backlash from anti-abortion groups that demanded President Trump fire the head of the National Institutes of Health, Dr. Francis Collins, for saying that research using fetal tissue could provide useful study for treatments of devastating illnesses.

The ban applies to scientists at NIH, the government's medical research agency, and would not apply to fetal tissue obtained from miscarriages, but only to fetal tissue that was donated after elected abortions. HHS, which is the NIH's parent agency, in September had already asked most government scientists to temporarily halt the acquisition of new fetal tissue while it reviewed the issue.

The new ban does not apply to outside groups that receive NIH grants to conduct their research, though HHS did announce it would not be renewing a multi-million dollar contract with the University of California, San Francisco, that used fetal tissue in HIV research.

The contract has been renewed every 90 days since the end of September as federal officials have reviewed it, but it won't be extended past Wednesday, when it was set to expire.

UCSF Chancellor Sam Hawgood said in a statement that the university "strongly opposed" the "abrupt" decision, and said the scientists specifically required fetal tissue to conduct their research.

"UCSF exercised appropriate oversight and complied with all state and federal laws," Hawgood said. "We believe this decision to be politically motivated, shortsighted and not based on sound science."

From now on, other outside researchers who get government funding will undergo an ethical review process by an NIH advisory board when they apply to have their grants renewed.

Anti-abortion groups welcomed the news. Marjorie Dannenfelser, president of the anti-abortion advocacy group Susan B. Anthony List, said in a call with reporters that she was pleased to see Collins implement the Trump administration's decision.

"The process was one of great integrity," she said.

But Megan Donovan, senior policy manager of the Guttmacher Institute, which supports abortion rights, said medical research would suffer and that the move was part of a "long-standing campaign to target abortion providers and stigmatize abortion care."

“Fetal tissue research is subject to stringent laws and regulations and has been for decades," she said. "Ideologues should not be allowed to stand in for real doctors and scientists when the government is making decisions about life-saving medicine.”

The decision from HHS came after discussions with anti-abortion advocates, scientists, ethicists, and patient advocates. It started in September 2018, when HHS ended a contract the Food and Drug Administration had with Advanced Bioscience Resources, Inc., after saying that it was "not sufficiently assured that contract included the appropriate protections applicable to fetal tissue research or met all other procurement requirements."

At that time, the agency also decided to have its staff review research involving fetal tissue to make sure that it was following all regulations and laws and that it was receiving proper oversight.

Republicans have called for ending research using fetal tissue since the anti-abortion Center for Medical Progress released videos that appeared to show Planned Parenthood staff discussing the sale of fetal tissue, a practice that is illegal. Planned Parenthood has denied wrongdoing, and state investigations have not found evidence that the organization illegally sold fetal tissue for profit.

House GOP Whip Steve Scalise of Louisiana praised the Trump administration's move to end the UCSF research grant.

"It is reprehensible for anyone to profit from the tragedy of abortion and the Trump administration is making that clear by saying no to this ethically tainted research," he said.

Outside groups opposed to fetal tissue research are not just opposed to abortion, but contend the practice of using the tissue in experiments is degrading, wrong, and unnecessary. They question whether fetal tissue research is effectual and believe other types of tissues work better and should be used instead — adult stem cells, umbilical cord, amniotic fluid, tissue from the placenta, or discarded tissue from surgery on an infant.

"Most Americans do not want their tax dollars creating a marketplace for aborted baby body parts which are then implanted into mice and used for experimentation," said Jeanne Mancini, president of March for Life, an anti-abortion advocacy group. "This type of research involves the gross violation of basic human rights and certainly the government has no business funding it.”

While many other scientists and medical advocacy groups are open to the possibility of alternatives in the future, they maintain that fetal tissue has unique properties that make it work best for certain research.

Organizations such as the Association of American Medical Colleges , the Michael J. Fox Foundation , the AIDS Healthcare Foundation, and the National Multiple Sclerosis Society oppose efforts by House Republicans to ban government funding on the research, saying it could hamper medical efforts to understand birth defects, develop cures for infectious diseases, and tackle chronic illnesses such as Parkinson’s disease.

In December, NIH appeared to try to assuage anti-abortion critics by announcing that it would award $20 million over two years to scientists who study alternatives to fetal tissue.

"They are looking at putting more money toward validating these current alternatives ... this is the best science," said Dr. David Prentice, vice president and research director at the Charlotte Lozier Institute, the research arm of Susan B. Anthony List.