DES was created as the first synthetic oestrogen by Sir E. Charles Dodds and his team in England. DES was not patented because Dr. Dodd’s discovery was funded by the British government with a policy that inventions from government-sponsored research be available to all. This allowed pharmaceutical companies access to a drug that was cheap and easy to produce. DES was developed for short-term use for menopause symptoms. It was not designed to be given to pregnant women, this use occurred several years later.

DES was about five times more potent than natural oestradiol. Because it was cheap to produce and not patent-protected, over 200 pharmaceutical firms manufactured DES under various brand names (in the UK it was commonly called stilboestrol).

From the 1940s through the 1960s, doctors prescribed DES to pregnant women with a history of miscarriages, preterm labour, or diabetes, aiming to improve pregnancy outcomes. It was even suggested as a routine prenatal supplement for “bigger and stronger babies.”

In 1947, the US FDA approved DES specifically to prevent miscarriage, leading to its widespread use in North America, the UK, Europe, and elsewhere.

Despite rapid adoption, evidence soon showed DES did not prevent miscarriages. A 1953 trial found no benefit, with higher pregnancy loss rates in women on DES. Animal studies raised safety concerns: a 1940 report noted DES caused cancer in mice, leading to a 1959 ban as a growth additive in US chicken feed after residues caused hormonal side effects in consumers. Despite this, pharmaceutical companies marketed DES, dismissing negative findings, and it was prescribed worldwide through the 1960s for various medical purposes.

In 1971, doctors observed young women developing a rare vaginal/cervical cancer called clear cell adenocarcinoma (CCA), linked to prenatal DES exposure. A study in the New England Journal of Medicine confirmed this association. The US FDA advised against using DES in pregnancy in April 1971, leading to its cessation by the mid-1970s (although some prescriptions persisted into the early 1970s in the US and late 1970s in Europe).

DES is now recognised as an endocrine disruptor causing cancer, birth defects, and developmental abnormalities. Today, DES use is rare, limited to advanced prostate cancer cases when other treatments fail.