She also switched sides, from abortion rights advocate to anti-abortion campaigner. She underwent two religious conversions, as a born-again Christian and as a Roman Catholic, and became in her last decades a staunch foe of abortion, vowing to undo Roe v. Wade, testifying in Congress and bitterly attacking Barack Obama when he ran for president and then re-election.

She was never the idealized Jane Roe crusader many Americans visualized. Some observers said she became a pawn used by both sides in the maelstrom of the abortion wars as her public views shifted from one side to the other. In her first book, “I Am Roe: My Life, Roe v. Wade, and Freedom of Choice” (1994, with Andy Meisler), she offered what was perhaps her own most objective self-assessment.

“I wasn’t the wrong person to become Jane Roe,” she said. “I wasn’t the right person to become Jane Roe. I was just the person who became Jane Roe, of Roe v. Wade. And my life story, warts and all, was a little piece of history.”

Plucked from obscurity in 1970 by Sarah Weddington and Linda Coffee, two young Dallas lawyers who wanted to challenge Texas laws that prohibited abortions except to save a mother’s life, Ms. McCorvey, five months pregnant with her third child, signed an affidavit she claimed she did not read. She just wanted a quick abortion and had no inkling that the case would become a cause célèbre.

Four months later, she gave birth to a daughter and surrendered her for adoption. (Her second child had also been given up for adoption, and her first was being raised by her mother.) She had little contact with her lawyers, never went to court or was asked to testify, and was uninvolved in proceedings that took three years to reach the Supreme Court.

On Jan. 22, 1973, the court ruled 7-2 in Roe v. Wade (Henry Wade, the Dallas County district attorney, was the defendant in the class-action suit) that privacy rights under the due process and equal rights clauses of the 14th Amendment extended to a woman’s decision to have an abortion in a pregnancy’s first trimester “free of interference by the state,” in the words of Justice Harry A. Blackmun, who wrote the opinion.