Pro-choice advocates Drew Angerer | Getty Images

With the stroke of a pen, President Donald Trump reinstated a controversial rule that blocks foreign aid for family planning services. Known as the "Mexico City policy" or the "Global Gag Rule," the policy bars foreign aid or federal funding for international programs that provide abortions — or even information about the procedure. Under the rule, USAID would be unable to provide funds to non-governmental organizations that provide referrals or counseling for abortion services, or advocate for the same. NGOs that provide abortions — except in the case of rape, incest or life endangerment — would also be ineligible for aid. More from NBC News:

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Trump focuses on economy after inauguration feud Much of the agency's family planning aid is aimed at reducing maternal and infant mortality, both through preventing unintended pregnancies and allowing families to better space childbirths.





This is President Trump taking us back to 1984, and the world has changed very much since then... We do expect it to cost women their lives. Serra Sippel president, Center for Health and Gender Equality

Established in 1984 by President Ronald Reagan, the global gag rule has since become a political football that has been repeatedly rescinded and revived depending on which party controls the White House. Democratic President Bill Clinton nixed it. Republican President George W. Bush brought it back. Democratic President Barack Obama threw it out almost immediately after his inauguration. And now, Trump has reinstated it as part of what critics fear will be a broad effort to undermine reproductive rights at home and abroad. Pro-choice groups see the law's return as a step backwards after years of progress. Serra Sippel, president of the Center for Health and Gender Equality, said that in addition to reducing women's access to contraceptives and safe abortions, the measure could hamper HIV prevention efforts abroad and force health clinics in developing countries to close their doors. "This isn't just a reinstatement of an existing policy," Sippel said. "I think how we're looking at it is: This is President Trump taking us back to 1984, and the world has changed very much since then. This is Trump's global gag rule, and we do expect it to cost women their lives." Pro-life groups, on the other hand, applauded the rule's return. Carol Tobias, president of National Right to Life, cited polls that showed a majority of Americans did not support the use of tax dollars for abortion services.