historyWellcome Collection1957–1961 · West Germany and UK

Thalidomide, a bitter pill

the gist

Thalidomide was developed by the German company Chemie Grünenthal as a non-addictive sedative, and was marketed for morning sickness, anxiety and insomnia in pregnancy even though it had almost no clinical testing on pregnant women. It was licensed in the UK in 1958 under the name Distaval and withdrawn by late 1961, after it became clear that taking it in early pregnancy could cause severe limb and organ damage. Of around 147,000 thalidomide-affected pregnancies worldwide, only about 24,600 resulted in live births. Survivors and mothers have spoken of the trust placed in doctors who did not know the drug's risks.

how it works

Thalidomide crossed the placenta and interfered with the development of the foetus, particularly the limbs, during a critical window of early pregnancy. Because the drug was thought to be harmless, testing had not examined its effects on the developing embryo.

so what

Thalidomide changed drug regulation, leading to stricter testing requirements for medicines given to pregnant women. It remains a central case study in why independent clinical trials matter.

the bigger pattern

Thalidomide's withdrawal led to tougher testing rules for medicines, and the same lesson of testing drugs on pregnant women and their babies remains part of drug regulation today.

Wellcome Collection · CC BY 4.0

Illustrative photo · Gadogado123, CC BY-SA 4.0, via Wikimedia Commons