Two days after millions of women around the world marched on behalf of women’s rights, President Donald Trump reinstated the Mexico City Policy.

In an executive order, Trump reinstated the rule on Monday. The Mexico City Policy prohibits foreign aid from the U.S. to be given to any nongovernmental organization (NGO) abroad that discusses abortion as a family-planning option. Currently, taxpayer dollars cannot be used to fund abortion procedures in other countries, but the order expands that oversight and also prohibits organizations from receiving U.S. family planning funding if they offer abortion counseling or advocate for abortion rights in other countries — even if the medical procedure is legal in that country.

The rule has gone back and forth between Administrations since it was first introduced in 1984 at the U.N. International Conference on Population held in Mexico City. In 2009, former President Barack Obama revoked the ruling as one of his first executive actions. It had been reinstated by former President George W. Bush after Bill Clinton’s Administration and was first introduced by former President Ronald Reagan.

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The policy forces health providers to decide whether to accept the ruling and no longer provide abortion-related counseling services, or reject it and lose U.S. funding that many rely on. Several health and development groups expressed concern about the possible implications on women’s health abroad. The U.S. Agency for International Development (USAID) is currently the largest bilateral donor of funding for family-planning services, and studies reveal that when the Global Gag Rule is implemented, the number of clinics and family services in a given country drop, sometimes spurring a rise in abortion rates.

A 2015 report from the reproductive health group Population Action International (PAI) showed that after the rule was reinstated in 2001 by former President George W. Bush, shipments of U.S.-donated contraceptives stopped in 16 developing countries. A 2011 report from the World Health Organization found that abortion rates actually increased in sub-Saharan Africa after the rule was reinstated in 2001, likely owing to the fact that women no longer had the same access to contraceptives.

Marie Stopes International, a nonprofit reproductive-health group, said on Monday that it will not agree to the conditions, and therefore will no longer receive USAID funding. Until Monday, the group said it partnered with USAID to provide voluntary contraceptive services to millions of women and girls across Africa and Asia. Without the funding, the group says the loss of its services during Trump’s first term could result in 6.5 million unintended pregnancies, 2.2 million abortions, 2.1 million unsafe abortions and 21,700 maternal deaths.

“Attempts to stop abortion through restrictive laws — or by withholding family planning aid — will never work, because they do not eliminate women’s need for abortion,” Marjorie Newman-Williams, vice president and director of Marie Stopes International’s international operations, said in a statement. “This policy only exacerbates the already significant challenge of ensuring that people in the developing world who want to time and space their children can obtain the contraception they need to do so.”

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