Unrealistic. Despite uniformed opinions to the contrary women have filled support positions since they cooked meals and nursed the wounded in the revolution. Also, contrary to popular opinion, not all support positions have the luxury of being far form the front. The most notable of these, the most traditional, and the field in which more women have been captured is of course is nursing.
In order to be effective, mobile medical units (can't bring myself to type MASH after the TV show) have to be close to combat in order to be effective. Forty-Five minutes from the front might as well be all the way back to the nearest permanent base. Even today, in the 21st century when male nurses are more common than any point in history, I'd be willing to bet the farm that you couldn't field 1/10 the number of male nurses needed to adequately staff medical units.
That of course explains why we've had female POW's in every war. Until someone comes up with better plan for this and other situations that are risky, we'll never be able to eliminate risk.