On the other hand, Dr. Wicklund has little use for requirements like 24-hour waiting periods, or for assertions like those of Justice Anthony M. Kennedy, who said in a recent Supreme Court decision on abortion that the government had an interest in protecting women from their own decisions in the matter.

“It’s so incredibly insulting,” Dr. Wicklund said in the interview. “The 24-hour waiting period implies that women don’t think about it on their own and have to have the government forcing it on them. To me a lot of the abortion restrictions are about control of women, about power, and it’s insulting.”

Dr. Wicklund said she would put more credence in opponents of abortion rights if they did more to help women prevent unwanted pregnancies. Instead, she said, many of the protesters she encounters “are against birth control, period.” That is unfortunate, she said, because her clinic experience confirms studies showing that emphasizing abstinence rather than contraception may cause girls to delay their first sexual experience for a few months, but “when they do have intercourse they are much less likely to protect themselves with birth control or a condom.”

According to the Guttmacher Institute, about a quarter of pregnancies in the United States end in abortion. Dr. Wicklund says that is why she believes far more people favor abortion rights than are willing to admit it in polls. For example, she said in the interview, an abortion ban that seemed to have wide support in South Dakota was put to a vote and “when people got behind those curtains and nobody was watching it was overwhelmingly defeated. Unfortunately, people are not willing to say what they really think.”

One of these people might be a woman she recognized as one of the protesters who regularly appeared, shouting, outside a clinic where she worked. Only now the woman was in the waiting room, desperate to end an unwanted pregnancy. Dr. Wicklund performed the procedure.

And then there is Dr. Wicklund’s maternal grandmother, a woman she was afraid would disapprove of her work. But it turned out that she had a story of her own. “When I was 16 years old, my best friend got pregnant,” is how the story began. Her friend turned to her and her sister for help. They did the only thing they could think of — putting “something long and sharp ‘up there,’ ” according to the book. The girl bled to death, and the cause of her death was kept secret.

“I know exactly what kind of work you do,” the grandmother told Dr. Wicklund, “and it is a good thing.” One question Dr. Wicklund hears “all the time,” she said, is how she can focus on abortion rather than on something more rewarding, like delivering babies.