Dying during or just after a bypass operation happens more often to women than men, and no one knows why. "Finding an explanation...," said Dr. Fred H. Edwards, "...will require new research." Edwards, from the University of Florida Health Science Center, and his colleagues compared more than 50 risk factors and when they were done with allthe fact sifting, being female increased the chance of death during and after bypass surgery. One possible hint as to why women die more often than men during this common surgery is they usually have a different medical history than men before surgery.