Egyptian women of Nawal El Saadawi’s generation were expected to be docile, and never utter a word about sex.

But the feminist doctor and writer, who has died at the age of 89, was a fearless campaigner who smashed taboos in her fight against female genital mutilation and the double standards which deny women human and sexual rights. Controversial in her own country, Saadawi was imprisoned, had works banned and suffered death threats, but she refused to be muzzled. The author of more than 40 books, she helped shape the consciousness of millions of women in Egypt and around the world.

“Nawal’s impact was dazzling,” says Mozn Hassan, director of Nazra for Feminist Studies, a civil society group. “For me her book Women and Sex was an eye opener. When you read it as a teenager you see the world in a different way. You understand the meaning of patriarchy, power and repression. She was foundational.”

Born to a well-off family in the Nile Delta, Saadawi was the second of nine children. She quickly understood that sons were more valued than daughters, which she later said sparked her rebelliousness. But she was arguably most affected by trauma when, aged six, she was plucked from her bed to be circumcised — a harrowing experience she describes in her 1977 work The Hidden Face of Eve.

“I did not know what they had cut off from my body, and I did not try to find out,” she wrote. “I just wept and called out to my mother for help. But the worst shock of all was when I looked around and found her standing by my side. Yes, it was her . . . right in the midst of these strangers, talking to them and smiling at them.”

In 1955 Saadawi graduated from medical school and began treating girls after botched circumcisions. Egypt did not criminalise FGM until 2008, and it is still widely practised. Saadawi’s patients, and the physical and psychological problems they faced, fuelled her feminism and informed her writing. The 1972 publication of her seminal work Women and Sex, in which she discussed FGM and other problems faced by women, led to her dismissal from a senior position in the Ministry of Health.

A life-long socialist, she argued that patriarchy and capitalism, not Islam, were the root causes of female oppression. Her politics, outspoken views and criticism of former president Anwar Sadat, saw her imprisoned in 1981 — she was released two months later, following his assassination. While in prison, she continued to write her memoirs using an eyebrow pencil and toilet paper.

Saadawi attracted the ire of Islamists and in the early 1990s her name appeared on a death list drawn up by extremists. She began spending time abroad, where translations of her work had made her famous. But in her home country, where the rise of political Islam bolstered traditional views of women, Saadawi was marginalised and attracted hostility. In 2001, after she told an interviewer that Muslim pilgrimage rites contained “vestiges of paganism”, a lawyer sued to separate her from her third husband, Sherif Hetata, on the grounds that she was an apostate. Saadawi argued she was quoted out of context and the case was dismissed.

Her 43-year marriage to Hetata ended in divorce in 2010. She married her first husband, Ahmed Helmi in 1955, and had a daughter, Mona, but they broke up after two years. She was also briefly married to a lawyer. She is survived by Mona, a writer, and by Atef, her son with Hetata.

Despite the risks, Saadawi’s political activism continued. In 2004 she announced she was running for president — a symbolic act of opposition. In 2011, she was among the protesters in Tahrir Square who ousted Hosni Mubarak. But her impact extended far beyond the Arab world and she was seen as a key influence on feminists in the global south.

“Nawal Saadawi’s international influence is beyond what we can imagine in Egypt,” says Hassan. “Here many have viewed her as a crazy woman or as the daughter of the left, but . . . there are many people in the world who know only two things about Egypt: the pyramids and Nawal Saadawi.”

Winnie Byanyima, the Ugandan human rights activist and executive director of UNAids, was among many international figures who mourned Saadawi’s passing, tweeting: “She is one of the most influential feminist thought leaders and activists of the 20th century. An icon of the southern feminist movement, her contribution is unique and outstanding. RIP.”