DES was prescribed to prevent miscarriage — it gave millions of daughters cancer

Diethylstilbestrol (DES) was a synthetic estrogen first synthesised in 1938 and marketed from 1939. In 1947, the FDA approved it for preventing miscarriage, and it became one of the most widely prescribed drugs in America. At its peak in 1953, DES was given to millions of pregnant women despite a 1953 study showing it was ineffective at preventing miscarriage. The drug was also used in livestock as a growth promoter, and in chickens until 1959.

In 1971, a study in the New England Journal of Medicine linked DES to clear-cell adenocarcinoma, a rare vaginal and cervical cancer, in daughters exposed in the womb. Up to 2 million Americans had been exposed during pregnancy. Follow-up studies found that DES daughters also suffered from infertility, ectopic pregnancy, preterm birth, early menopause, and breast cancer. Some effects appeared in the grandchildren as well — transgenerational harm that skipped a generation.

The FDA withdrew the pregnancy indication in 1971 but did not fully withdraw DES approval until 2000. Eli Lilly, the last US manufacturer, stopped making it in 1997. In the landmark 1980 case Sindell v. Abbott Laboratories, the California Supreme Court imposed market share liability on all DES manufacturers, proportional to their market share — a legal precedent that reshaped product liability law. Over 1,000 lawsuits were pending by 1991. DES remains one of the largest pharmaceutical disasters in history.