For some women, the decision to have an abortion is agonizing, a source of lingering regret.

Longtime women's rights champion Harriet Hills Stinson revealed that she had an illegal abortion in her 20s. (Photo: Sarah Rice / Special to The Chronicle) For Harriet Stinson, it was a simple choice, one that she has never second-guessed. She had three children already when she became pregnant for a fourth time, and she didn't think she could handle the stress of another.

Stinson, a longtime leader of the Bay Area abortion-rights movement, shared her story for the first time publicly Wednesday in front of 600 people at a luncheon in Palo Alto put on by NARAL Pro-Choice California.

Now 85, the San Mateo resident said she disclosed this deeply personal chapter from her past to encourage other women to speak out about their experiences. She hopes to combat the stigma attached to abortion and reinforce the importance of sex education and contraception for young people.

"We've got to be bold and brave and do something drastic, and this is drastic," Stinson told the crowd at the Crowne Plaza Cabana Hotel.

Stinson becomes the second prominent Peninsula woman this year to relate the experience of having an abortion. During an emotional fight over funding for Planned Parenthood in February in the House of Representatives, Rep. Jackie Speier announced that she had to terminate a pregnancy nearly 20 years ago due to a medical complication when she was 17 weeks pregnant.

Stinson's history of leadership in the local abortion-rights arena includes founding a Planned Parenthood branch in San Mateo and starting the first U.S. jail family-planning program. She also established the now-defunct political group California Republicans for Choice, an organization that educated and backed Republican candidates who supported abortion rights.

Stinson was in her late 20s when she underwent her abortion.

She had been using birth control, but it failed. The lack of sleep from raising three young children was causing her such stress that she had the urge to act out violently toward them whenever her sleep was disrupted. Her late husband, an obstetrician, performed the procedure himself.

Today, Stinson has five grandchildren and one great-grandchild.

She said she adores her family and doesn't think it would have turned out the same if she hadn't made the choice to have an abortion nearly 60 years ago.

Three-fourths of women who undergo abortions say having the baby would interfere with their professional lives or their ability to care for dependents, according to research compiled by the Guttmacher Institute, a nonprofit organization dedicated to reproductive health. Abortions have been in a general decline since the late 1970s, according to the institute. The number of abortions per 1,000 women between the ages of 15 and 44 fell from 29.1 in 1981 to 19.6 in 2008.

Despite the drop in the rate of procedures, Stinson said abortion rights remain under attack. She said she'll be happy if her words Wednesday encourage others to step up and fight for those rights.

Liz Figueroa, of Planned Parenthood Mar Monte in San Jose, said Stinson serves as a good role model.

"Fearless is the word that comes to mind," she said. "These stories are not easy to tell. When you have leaders like that, it makes it so much easier to follow."