The study, which involved nearly 20,000 cases around the country, found only 39 percent of women suffering cardiac arrest in public received CPR, compared to 45 percent of men.
Men were also 23 percent more likely to survive a cardiac arrest occurring in public.
Researchers don’t know why exactly rescuers were less likely to assist women and did not find a gender difference in CPR rates for people suffering from cardiac arrest at home, where a rescuer is more likely someone who knows the person needing help.
“It can be kind of daunting thinking about pushing hard and fast on the center of a woman’s chest,” and some people may fear they are hurting her, said lead researcher Audrey Blewer, from the University of Pennsylvania.
And, according to Dr. Benjamin Abella, another study leader, rescuers may also worry about moving a woman’s clothing to get better access or touching breasts to do CPR.
But proper CPR shouldn’t entail that, Abella said.
“You put your hands on the sternum, which is the middle of the chest. In theory, you’re touching in between the breasts,” he said. “This is not a time to be squeamish, because it’s a life and death situation.”
The Mayo Clinic’s Dr. Roger White, who co-directs the paramedic program for the city of Rochester, Minnesota, said he has long worried that large breasts may impede proper placement of defibrilator pads if women need a shock to restore normal heart rhythm.
“All of us are going to have to take a closer look at this” gender issue, he said.
More than 350,000 Americans who may or may not have diagnosed heart disease suffer a cardiac arrest each year in areas other than a hospital, and about 90 percent of them die. According to the American Heart Association, CPR can double or triple survival odds.
The Associated Press contributed to this report.