Diethylstilbestrol (DES) drug bottle. This drug is a synthetic nonsteroidal oestrogen first synthesised in 1938. It was used to treat postmenopausal symptoms, vaginitis (inflammation of the vaginal mucosa), prostate and advanced breast cancer, and was thought to prevent miscarriages. It was also used in livestock to promote growth. However, it was found to be a teratogen, causing congenital defects when prescribed to pregnant women. Use of the drug in pregnant women was stopped in the 1970s, when use in livestock was also stopped as DES residue was found in animal tissue.