Doctors X-rayed pregnant women routinely in the 1950s to check which way round the baby was lying. Nobody thought it was dangerous.
Alice Stewart noticed childhood leukaemia rising sharply in Britain and set out to find why. She and her team interviewed the mothers of 1,400 children who had died of cancer, and 1,400 mothers whose children were alive, and asked them the same questions.
The pattern showed up in the first 35 pairs. Children who had died were about twice as likely to have been X-rayed in the womb, and a single scan at the dose used then appeared to be enough.
She published in 1956, and the response was outrage. Radiation was the technology of the future in the 1950s, and the claim that a low dose could cause cancer years later contradicted what the entire medical and nuclear establishment believed. Her methods were attacked. Her funding suffered. Doctors carried on X-raying pregnant women.
It took roughly 25 years for the medical world to come round. Pregnant women were still routinely X-rayed into the late 1970s. Two decades after she told them to stop. She retired in 1974 and did her most contested work afterwards, in her seventies, examining the health records of American nuclear weapons workers. Her findings there were unwelcome enough that the Department of Energy cut off her access to the data. She spent 14 years fighting them and testified before Congress, and in 1990 the records were opened to independent researchers.
She died in 2002, aged 95. The children who were never X-rayed have no idea who she was.
history.rcp.ac.uk/blog/alice…