People for a long time had been treated during their pregnancy with DES and there have been known to be toxic and adverse effects to the hormone therapy. "Exposure to DES has been associated with an increased risk for breast cancer in DES mothers (relative risk, <2.0) and with a lifetime risk of clear-cell cervicovaginal cancer in DES daughters of 1/1000 to 1/10 000." Side effects of DES are proving to be long-term as it can cause increased risks to cancer after use. There will be continued work to see how far the adverse effects of DES will go after previous therapy as many women had used this during pregnancy and there is a long line to see how it will effect offspring and the mothers longer-term. Regulations
In 1938, the ability to test the safety of DES on animals was first obtained by the FDA. The results from the preliminary tests showed that DES harmed the reproductive systems of animals. The application of these results to humans could not be determined, so the FDA could not act in a regulatory manner.New Drug Applications for DES approval were withdrawn in 1940 in a decision made by the FDA based on scientific uncertainty. However, this decision resulted in significant political pressure, so the FDA came to a compromise. The compromise meant that DES would be available only by prescription and would have to have warnings about its effects on the bottle, but the warning was dropped in 1945.
In 2013, the Fecho sisters who initiated the breast cancer/DES link litigation agreed to an undisclosed settlement amount on the second day of trial. The remaining litigants have received various settlements.The advocacy group DES Action USA helped provide information and support for DES-exposed persons engaged in lawsuits. Society and culture
Alan Turing, the ground-breaking cryptographer, founder of computing science and programmable computers, who also proposed the actual theoretical model of biological morphogenesis, was forced onto this medication to induce chemical castration as a punitive and discredited "treatment" for homosexual behaviour, shortly before he died in ambiguous circumstances.James Herriot describes a case regarding treating a small dogs testicular Sertoli cell tumor in his 1974 book All Things Bright and Beautiful. Herriot decided to prescribe a high dose of the new drug Stilboestrol for the recurring tumor, with the amusing side effect that the male dog became "attractive to other male dogs", who followed the terrier around the village for a few weeks. Herriot comments in the story that he knew "The new drug was said to have a feminising effect, but surely not to that extent." Veterinary use
Canine incontinence
DES has been very successful in treating female canine incontinence stemming from poor sphincter control. It is still available from compounding pharmacies, and at the low (1 mg) dose, does not have the carcinogenic properties that were so problematic in humans. It is generally administered once a day for seven to ten days and then once every week as needed.