Smoking out a source of painful menses

Roughly half of menstruating women regularly experience cramps. The pain, which can be debilitating, accounts for some 600 million hours of lost work time annually in the United States alone. A study now finds that exposure to secondhand smoke may trigger this common gynecologic disorder.

Changzhong Chen of the Harvard School of Public Health in Boston and his colleagues studied 165 nonsmoking women in China.