Patricia Maginnis, one of the nation’s earliest and fiercest proponents of a woman’s right to safe, legal abortions, who crusaded for that right on her own before the formation of an organized reproductive-rights movement, died on Aug. 30 in Oakland, Calif. She was 93.

Her niece Semberlyn Crossley said the cause of her death, in a hospital, was chronic obstructive pulmonary disease.

Ms. Maginnis, whom many consider the first abortion-rights activist in the United States, helped shift the debate in the era before Roe v. Wade away from the rules governing abortion providers to the right of women to control their bodies.

As Texas and other states pass or are considering laws drastically curtailing most abortions, her life is a reminder of the single-minded commitment it took to help secure the right to abortion, and of what women faced before the procedure was legalized.

“After all she went through, including risking going to prison, she couldn’t have imagined this kind of rollback,” Elana Bloom, Ms. Maginnis’s grandniece, said in a phone interview.

Ms. Maginnis “may not loom as large as a Margaret Sanger or a Betty Friedan” in feminist history, Lili Loofbourow wrote in Slate magazine in 2018, in the definitive profile of Ms. Maginnis.

“And yet,” she added, “a decade before Roe, with her ungainly activism, her proclivity for wearing clothes she’d found on the street and her righteous, unquenchable rage, Maginnis helped to fundamentally reshape the abortion debate into the terms we’re still using today.”

She founded the Citizens Committee for Humane Abortion Laws, which called for women’s right to safe and legal elective abortions, in San Francisco in 1962. The committee, which later changed its name to the Society for Humane Abortion, sponsored symposiums to educate medical and legal professionals and operated a free post-abortion clinic.

A few years later Ms. Maginnis, along with two colleagues, Lana Phelan Kahn and Rowena Gurner, formed the Association to Repeal Abortion Laws (ARAL), the precursor to NARAL Pro-Choice America, now one of the nation’s major abortion-rights advocacy organizations, which was founded in 1969.

The women became known as the “Army of Three” as they conducted a systematic civil disobedience campaign at a time when even mailing literature about birth control was illegal. They led classes in how to conduct do-it-yourself abortions and coordinated what they called an “underground railroad” of information, which provided, among other things, a continually updated list of qualified abortion providers in Mexico, Japan and Sweden.

In violation of local and state laws that prohibited telling women where they could “procure a miscarriage,” they also distributed leaflets on the streets of San Francisco doing just that and urging women to attend their do-it-yourself abortion classes.

“I am attempting to show women an alternative to knitting needles, coat hangers and household cleaning agents,” Ms. Maginnis told reporters in 1966.

The Army of Three flagrantly violated the law not only to help educate women but also so they could be arrested and test anti-abortion ordinances. Ms. Maginnis and Ms. Gurner were arrested in San Francisco in 1967 and convicted of unlawfully advertising abortion, but in 1973 a California appeals court overturned their convictions as unconstitutional, rendering the ordinances invalid.

Ms. Maginnis, who grew up in a strict Roman Catholic family in Oklahoma, told Slate that she couldn’t specify the moment she became an activist. Rather, she said, she seemed to reach the boiling point after a long, slow buildup of rage — after she tended to women with botched abortions at an Army hospital; after she saw how powerless women were in the face of bureaucratic medical protocols; after she saw the wide disparities in how poor women and women of color were treated compared with women of means; and after she had three abortions herself, one performed in Mexico and two that were self-induced.

Regardless of when her activism began, her agenda of repealing all abortion laws and teaching women to self-induce seemed so far out of the mainstream that some in the news media treated her with derision. A New York Times article in 1966 about her abortion classes said she had “the eyes of a zealot” and identified her, at 38, as a “spinster.”

Alternative newspapers called her “the Che Guevara of abortion reformers,” a reference to the guerrilla strategist of the Cuban revolution. Her ideas certainly went beyond the calls for incremental reform made by establishment groups like Planned Parenthood.

Ms. Bloom, her grandniece, said there were several reasons Ms. Maginnis was not embraced by the mainstream. “She was teaching women how to give themselves abortions,” she noted, “which, even by today’s standards, is pretty radical.”

Beyond that, she said, Ms. Maginnis was not a self-promoter. “She was just trying to legalize abortion at any cost.”

Patricia Therese Maginnis was born on June 9, 1928, in Ithaca, N.Y., where her father, Ernest, was attending veterinary school at Cornell University. After graduating during the Great Depression, he found work in Oklahoma, though the family was never well off. They settled first in Tulsa, then in Okarche, part of the Oklahoma City metropolitan area, where Pat grew up with six siblings. Her mother, Miriam (Mansfield) Maginnis, was a schoolteacher.

Pat learned early about the consequences of unplanned pregnancies. Her mother had medical issues and doctors had advised her against having more children, but she and her husband did not believe in birth control and continued to have them, despite her pain.

As for her father, Ms. Maginnis told Slate, his parents were not married, and he never got over the shame. His mother was an opera singer, and his birth had ended her career.

Ms. Maginnis boarded at a convent school about 40 miles from home. After she graduated in the mid-1940s, she became a lab technician.

She then joined the Women’s Army Corps and was stationed at Fort Bragg, N.C. When an officer saw her walking with a Black soldier, she was reprimanded and sent to Panama as punishment.

There she was assigned to work in the Army’s pediatrics and obstetrics wards, where she saw women suffering from botched abortions as well as women being forced to give birth to babies they didn’t want.

After leaving the Army, she attended San Jose State College (now University) in California, where she became pregnant. She had been fitted for a diaphragm, but it hadn’t worked. Partly because of her parents’ examples, she was determined not to have the baby and ended up going to Mexico to have an abortion.

Once the Supreme Court ruled in its landmark Roe decision in 1973 that women had a constitutional right to abortion, Ms. Maginnis rechanneled her activism to other issues, including gay rights and animal welfare. She also staged regular protests against the Catholic Church, criticizing its anti-abortion policies and demanding accountability in cases of sexual abuse by priests.

In addition to a large extended family, Ms. Maginnis is survived by two sisters, Charlotte Palmer and Jane Bloom, and two brothers, Michael and Paul.

Always self-reliant, she bought a two-story Victorian house in East Oakland in 1979 and devoted much of her time to restoring it. It had been gutted by fire, and it had no foundation. But she created one by digging a two-foot trench around it herself with a serving spoon and hauling the dirt away in a small pot, which took her an entire year.

In her later years, she didn’t talk much about abortion unless asked. Ms. Bloom, her grandniece, said that she didn’t even know about Ms. Maginnis’s work until she was a student at Smith College and saw a documentary in which her great-aunt appeared.

“Even though the ‘Army of Three’ comes up in women’s studies courses,” Ms. Bloom said, “no one is reading whole books about them. And a lot of younger feminists don’t know about them.”