The 41st annual March for Life went on, despite a temperature of 10 degrees and numerous cancellations by participants unable to make travel connections because of a snowstorm Tuesday, the Washington Post reported, noting the weather canceled a 5K run and forced a pre-rally concert to be scaled back.
The march coincided with the anniversary of the landmark 1976 U.S. Supreme Court decision, known as Roe vs. Wade, permitting abortion.
The March for Life, which promotes itself as the world's largest anti-abortion event, is under new management this year after the 2012 death at 88 of founder and former President Nellie Gray.
While abortion opponents praise her legacy, the focus of the event has changed from a one-day, Catholic-centered demonstration to an attempt at building a permanent political machine, CNN said.
The staff and budget of the March has doubled since 2012, and this year's theme concentrates on adoption, which March President Jeanne Monahan said demonstrates activists are reaching out to a new generation who seem more open to the March's message if it is seen as less politically partisan and more empathetic to pregnant women.
Abortion rights advocates note the percentage of Americans who approve of overturning the Supreme Court decision has hovered at about 30 percent since 1989, suggesting the March for Life is not influencing changes of opinion.
"It's an impressive show, but at the end of the day, they have failed dramatically at their goal," said Jon O'Brien, president of Catholics for Choice.
"You've got all these young people [at the March] with energy and passion and they desire to do something about the injustice of abortion, but what do they do when they leave the march and go home?" anti-abortion activist Ryan Bomberger said.
March for Life has hired a full-time lobbyist and a social media manager, and seeks to turn its youthful corps of protesters into citizen lobbyists similar to Tea Party partisans or the young voters involved in President Barack Obama's presidential campaigns, CNN said.
The White House issued a statement Wednesday noting the anniversary of Roe vs. Wade, saying, "We reaffirm our steadfast commitment to protecting a woman's access to safe, affordable health care and her constitutional right to privacy, including the right to reproductive freedom."