The president didn't attend in person but spoke to the crowd via video.
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"This is a movement founded on love and grounded in the nobility and dignity of every human life," he said. "As president, I will always defend the first right in our Declaration of Independence, the right to life."
Both Democratic and Republican lawmakers have been highlighting the abortion issue leading up to the march.
Pence credited the president for nominating conservative judges to the federal bench during his address.
Pence was clear in his support for the marchers, calling their plight one of "compassion."
"We gather here because we believe as our founders did that we are, all of us, born and unborn, endowed by our creator, with certain unalienable rights and first among these rights is the right to life," Pence said.
The march first began in January 1974, a year after the Supreme Court released its verdict in Roe v. Wade.