 DES (diethylstilbestrol) is a drug that mimics estrogen, a female hormone.From 1938 until 1971 doctors prescribed this drug to help some pregnant women who had had miscarriages or premature deliveries on the theory that miscarriages and premature births occurred because some pregnant women did not produce enough estrogen naturally to sustain the pregnancy for full term .An estimated 5-10 million pregnant women and the children born during this period were exposed to DES.