Tens of thousands of anti-abortion activists marched in the US capital, Washington, DC, spurred on by the election of Donald Trump who has vowed to end taxpayer-funded abortion.
Vice President Mike Pence, a longtime supporter of the anti-abortion movement, was the most senior government official to speak at Friday's rally.
"Life is winning again in America," Pence told the demonstrators who hoisted signs saying "Choose life", "I am the pro-life generation" and "Equal Rights For Unborn People".
Pence, who as governor of Indiana signed some of the nation's strictest abortion laws, praised "the election of pro-life majorities in the Congress of the United States of America".
On Tuesday, Trump signalled his intention to nominate an anti-abortion justice to the Supreme Court and has already revived an old policy banning funding for groups abroad that pay for abortions or provide information about abortion.
Al Jazeera's Shihab Rattansi, reporting from the rally in Washington, DC, said many of the protesters were optimistic that they had an ally in the new president.
"Many of the protesters hope that a Trump-nominated justice will help overturn the landmark Roe v Wade ruling in 1973 that a woman has the right to make her own medical decisions without any interference from politicians," he said.
Trump has said Roe v Wade should be overturned. He has also pledged to defund Planned Parenthood, which draws the ire of many Republicans because it provides abortions, along with other services.
Dana Tilson, the Kenya director for Marie Stopes International, a family-planning clinic, told Al Jazeera that cutting funding to abortion providers could see poor women across the world turn to dangerous methods to end their pregnancies.
"If women and girls are denied safe options, they will seek any method to end a pregnancy," she said.
"They will go to the streets and will be served by unskilled providers who use chemicals and sticks and other mechanisms that will damage their reproductive organs and some cases result in them bleeding to death."
The rally comes as the number of US abortions has fallen to a record low. The Guttmacher Institute, a reproductive health and rights organisation, said last week that it dropped below 1 million in 2013 for the first time since 1975.
A Quinnipiac University poll released on Friday showed that 64 percent of Americans say abortion should be legal in all or most cases, while 31 percent said it should be illegal in all or most cases.
Source: Al Jazeera and news agencies