DES Cancer Network

Timeline: A Brief History of DES (Diethylstilbestrol)

DES, diethylstilbestrol, is a drug that was given to millions of pregnant women, primarily from 1938 to 1971. This synthetic hormone was touted as a "wonder drug" and widely prescribed in the mistaken belief that it could prevent miscarriage. In addition to having no effect on miscarriage, it has resulted in health problems for the women who took the drug as well as their daughters and sons.

1938: Diethylstilbestrol (DES) created. DES was the first synthetic estrogen ever synthesized; it was cheap to produce, more potent than natural estrogen, and could be taken orally. In the rush to make and market DES, Eli Lilly became one of the drug's major manufacturers. In America alone there were 267 drug companies that made and distributed DES and other similar synthetic estrogens because it was unpatented and easily produced. From the start, studies showed that DES promoted cancer in lab animals:

1938: Mice exposed to DES developed breast cancer.

1939: A rat exposed to DES developed mammary carcinoma.

1939-1940: Mice exposed to DES were born with malformed reproductive organs.

1941: DES approved for medical use in human beings. Despite the evidence from animal studies, the FDA approved the use of DES to treat vaginitis, gonorrhea, menopausal symptoms, and to suppress lactation - but not for use during pregnancy. Once FDA approval was granted for these limited uses, however, there was nothing to prevent drug salesmen from suggesting, and physicians from prescribing, DES for any other medical condition – menstrual problems, morning sickness, infertility, and many other applications.

1947: DES approved for use during pregnancy. At the prodding of the drug companies reacting to market demand, the FDA approved the use of DES during pregnancy. No controlled studies had been conducted by the drug companies to determine the effectiveness or safety of DES for use during pregnancy. DES was initially recommended for women with conditions such as diabetes, or those at high risk for miscarriages; however, it was soon widely prescribed to women with no apparent problems at all, and was the active ingredient in some "vitamin" tablets given to healthy pregnant women.

1952: Some scientists began to publicly question the efficacy of DES. The largest and best publicized controlled study of DES at the University of Chicago in 1953 showed it had "no beneficial effect whatsoever" in the prevention of miscarriage, and, in fact, DES brought about higher rates of premature birth and infant mortality. These findings were supported by several other studies done in the 1950s.

1959: DES banned in chicken and lambs. DES was used widely in agriculture beginning in 1941 to fatten livestock and chickens. Exposed male agricultural workers suffered sterility and breast growth as a consequence. When high DES levels in poultry produced similar symptoms in consumers as well, the FDA banned the use of DES in chicken and lambs in 1959.

Late 1960s: Six of the seven leading obstetrics textbooks stated that DES had no effect in preventing miscarriage in any group of patients. DES was still being prescribed to pregnant women and touted as a "wonder drug."

1970: Unprecedented appearance of rare cancer in young women. A rare vaginal cancer, CCA (clear cell adenocarcinoma), began to show up in unprecedented numbers in young women. 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.

1971: Doctors confirmed the link between CCA and DES. The findings of the Boston doctors were published in the New England Journal of Medicine, April 22, 1971. Only then did the FDA issue an alert advising against the use of DES during pregnancy. Even so, some physicians in the U.S. continued to prescribe it for a few years to pregnant women despite the FDA alert. Companies continued to sell DES overseas even after 1971; while it was no longer used in most western European nations by the late 1970s, DES continued to be sold through the 1980s in much of the rest of the world.

1978: DES Action formed -- a national non-profit organization representing mothers, children, and now grandchildren exposed to DES. The organization provides a newsletter, physician referrals and updated health information, as well as advocacy for continued research.

1979: DES banned in animal feed. Cattle breeders fought regulation of DES in feed until the Department of Agriculture finally banned it in 1979, but there were reports of its covert use through the early 1980s.

1982: DES Cancer Network formed. The DES Cancer Network is an international, non-profit, consumer organization that addressees the special needs of women who have had clear cell adenocarcinoma of the vagina or cervix – a cancer linked to exposure to DES before birth. The DCN provides recovered patients with ways to contact one another and to support new patients who have been diagnosed or are undergoing treatment. The DCN is also a support group to the family and friends of DES daughters who are clear cell cancer survivors as well as those who have lost loved ones to the disease. In addition, we serve as a resource to health care professionals and attorneys whose patients/clients have had clear cell cancer. The DES Cancer Network has been serving DES cancer daughters since 1982.

1992: National Institute of Health (NIH) convened the first-ever meeting on the long-term effects of DES.

1992: DES bill passed. Congress unanimously passed the DES Education and Research Amendment (chief sponsors Rep. Louise Slaughter [D-NY] and Sen. Tom Harkin [D-IA]), providing funding to the National Institute of Health for research on mothers and children, and for a public and physician education campaign.

1993: Long-term DES research is expanded. The NIH began new studies on the long-term medical effects of DES, such as breast cancer in the daughters, immune system disorders, and reproductive problems in the sons, as well as the long-term health effects of the various treatments for CCA.


    Since 1971, the devastating effects of DES exposure discovered include:
  • Structural damages in reproductive organs of DES sons and daughters;
  • High risk pregnancies and miscarriage for DES daughters;
  • Increased risk of clear cell cancer of the vagina and/or cervix in DES daughters;
  • Increased risk for infertility in DES sons and daughters;
  • Increased risk of breast cancer in DES mothers and DES daughters over 40 years of age;
  • Possible immune system impairment in some mothers and children exposed to DES.
There are an estimated 10 million DES mothers and children in the United States today. Current statistics indicate that one in a thousand DES-exposed daughters will get CCA, the clear cell cancer originally linked to DES in 1971.

To this day, none of the 267 pharmaceutical companies who produced and distributed DES has accepted any responsibility for the DES tragedy, and all continue to claim that DES causes no health problems. Eli Lilly, the largest manufacturer, has been a defendant in the majority of lawsuits brought by victims of DES-related cancer, infertility, and birth defects.

Researchers are still uncovering frightening facts about the life-long effect of exposure to DES, including higher rates of breast cancer in DES mothers, reproductive abnormalities in daughters and sons, higher rates of ectopic pregnancy in daughters, and damage to the endocrine and immune systems. Effects on the third generation - DES grandchildren - are as yet unknown. To this day, no studies have been done on the long-term effects of DES exposure on agricultural workers, nor is the impact of exposure on pharmaceutical company employees known.

The DES issue will not be finished until this entire generation of DES-exposed mothers, daughters, and sons is gone. Every physician and health care provider must be aware of what it means to be DES exposed and be educated to treat their patients in the best possible way.


The DES Cancer Network is no longer responding directly to email inquiries.  If you have a general (non-cancer) DES-related question or concern, please contact DES Action by calling the toll-free information line at 1-800-337-9288 or by sending a message tot desaction@columbus.rr.com. The Web site address is www.desaction.org.  

If your question or concern is cancer-related please go the  University of Chicago, DES Cancer Registry website at www.obgyn.bsd.uchicago.edu/registry or contact them directly by phone at 1-773-703-6671 or by email at danderso1@babies.bsd.uchicago.edu.

If you need to talk to someone about support for yourself or a family member, the moderators of both of the Web sites above will direct you to a DES-related clear cell cancer survivor.