The idea arose--as ideas often do--at the starting line of a race. "I got into a conversation with some of the other women runners," recalls marathon-running physician Mona Shangold. "When they found out I was a gynecologist they started asking me lots of questions.

"They said their own gynecologists didn't know much about the special concerns of athletes. This happened over and over at races, and I realized there were a lot of active women who had a strong need for this kind of information."

In July 1981, Dr. Shangold--who currently runs 30 miles per week--opened the country's first Sports Gynecology Center at New York Hospital/Cornell Medical Center, where she treats women athletes and conducts "about a dozen" different research projects. Her studies--funded in part by Playtex Tampons--include the impact of exercise on female infertility, menstrual irregularities, bone density and age of puberty.

Two gynecological problems more common to women who participate in sports regularly, says the 34-year-old physician, are menstrual irregularity and amenorrhea (cessation of menstrual periods). "My own studies have found that 24 percent of marathon runners experience menstrual irregularity or amenorrhea," she says, "which is considerably higher than the estimated 5 percent incidence in the general population.

"While some people have attempted to incriminate exercise in this association, it is by no means so simple to determine cause and effect. A training program involves many more variables than just exercise . . . (training) may be accompanied by changes in body weight, body fat, diet, sleep and physical and emotional stress."

Although "exercise produces both immediate and long-term effects on the concentrations of many hormones," she notes that "emotional stress also affects hormone concentrations." Since most athletes with amenhorrea or irregularity also experienced these problems before they became athletes, she says, the problem may be rooted in the personality that leads someone to distance running rather than the running itself.

"Distance runners," she notes, "tend to be intelligent, educated, ambitious and disciplined." Exactly the type of women, she says, who may have the highly-motivated, stress-inclined personality associated with menstrual disorders.

There is, however, at least one potentially exercise-related cause of amenorrhea. "Amenorrhea can develop in thin women," she notes, "or in women--athletic or not--who lose significant weight or body fat." The average "fit woman," she says, has 25 percent body fat, while serious women runners may have as little as 10 percent body fat.

Athletes with menstrual irregularities should consult a gynecologist, advises Dr. Shangold, who recommends contacting area running clubs for recommendations of physicians sensitive to the concerns of female athletes. "She can generally continue training while undergoing evaluation," Dr. Shangold says. "It should never be assumed that an athlete's amenorrhea is either due to or related to the exercise. But it is wise to check into the problem, since lack of menstruation is associated with certain kinds of cancer."