DES (diethylstilbestrol), a toxic and carcinogenic synthetic estrogen, is considered one of the world’s biggest drug disasters. It was prescribed to millions of pregnant women for decades: from 1938 until 1971 (and in a small number of cases for several years thereafter) in the United States; and until the mid-1980s in parts of Latin America, Europe, Australia, and the Third World. The currently proven effects of exposure include a rare vaginal cancer in DES Daughters; greater risk for breast cancer in DES Mothers; possible risk for testicular cancer in DES Sons; abnormal reproductive organs; infertility; high-risk pregnancies; and an increased risk for breast cancer in DES Daughters after age 40. There are a number of other suspected effects, including auto-immune disorders, but many of these effects are still awaiting further research.
For decades, Big Pharma claimed DES prevented miscarriages and problem pregnancies. It was sometimes given as an injection, but primarily it was prescribed in pill form. Never patented, DES was marketed under 200 different names, although the majority of the drug was actually produced by Eli Lilly. DES was sometimes even included in prescription prenatal vitamins.
As early as 1938, studies showed that DES promoted cancer in lab animals. But at that time, people thought animal studies only provided a hint of what could happen in humans. Also, no one knew that drugs could cross the placenta and affect a baby in utero. (Note there was a 1941 mouse study that showed mice with absent or deformed fallopian tubes. The warning signs were there for humans.)
No controlled studies were ever conducted by the drug companies to determine the effectiveness or safety of DES for use during pregnancy, even after some scientists started questioning its efficacy in the 1950s. As early as 1953, research revealed that DES did not work – that DES actually brought about higher rates of premature birth and infant mortality – yet DES continued to be prescribed to pregnant women for decades. This is because pharmaceutical companies continued to heavily promote DES use to doctors. The drug was a top moneymaker for Big Pharma.
In the late 1960s, there was an unprecedented appearance of rare cancer in young women. Clear cell cancer (CCA) – a rare cancer of the vagina – was diagnosed in an age group never before found to develop it. (Normally elderly women developed CCA.) There were eight such cases at Massachusetts General Hospital in Boston alone. One of the mothers raised the question of whether her daughter’s cancer might be connected to DES exposure in utero. Doctors discovered the DES link in 1971 and published their findings in the April 1971 issue of New England Journal of Medicine. News of the cancer cases made national headlines. However, the FDA did not act on this information until public pressure forced the FDA to contraindicate DES during pregnancy in November 1971. DES was never banned for human use.