For years, it has been associated with cervical cancer and a rare vaginal cancer in younger women, but since 2002, studies have linked DES to breast cancer as well.
Diethylstilbestrol (DES), a synthetic hormone also known as Stilboestrol, was given to pregnant women to lower the risk of miscarriage beginning in the 1940s and into the mid-1970s. The drug was withdrawn from use for this indication in 1975, after its dangers to mothers and their unborn children became apparent.
Those women exposed to the drug suffered from infertility due to withered fallopian tubes and faced five times the risk of ectopic pregnancy. They were also up to three times more likely to miscarry, according to the August 7, 2006 Daily Mail.
When the problems caused by exposure in the womb became known, DES daughters were advised to have annual exams with smears taken from the vagina and cervix, and those women with vaginal tissue abnormalities, such as adenosis, were found to have nearly 50% more auto-immune diseases than DES daughters without such abnormalities.
Medical experts say the biggest problem has been that no one knows how many women took the drug and therefore people need to be made aware of the problem so they can ask their mothers if they recall taking DES during pregnancy and seek proper screening and care.
"Worldwide," according to the Daily Mail article, "six million women are believed to have taken it," before the drug was withdrawn in 1975, when studies revealed its adverse effects on unborn children.
In promoting DES, drug companies urged doctors to give pregnant women the drug to ensure they had bigger, stronger babies. "It was 'given out like Smarties,' to prevent miscarriage and complications of pregnancy including morning sickness and high blood pressure," according to the Daily Mail.
The public became more aware of the issue when DES Action support groups began to form in the mid-1970s after a 1974 article in Ms Magazine advised young women exposed to DES in the womb to seek special gynecological exams, and mothers who had taken the drug began to organize for mutual support. DES Action now has affiliated networks of men and women who were exposed to DES in countries all over the globe.
It is now known that DES was also prescribed for other indications as well. During the 1960s, teenage girls in America were sometimes prescribed DES to stop them from getting too tall and in some cases these tall girls suffered double exposure because their mothers were given the drug during pregnancy.
The 2001 summer issue of the DES Action/USA Voice Newsletter features the experience of Chris Cosgrove, who was prescribed DES to stop her from getting too tall. Chris originally wrote her story for the May 2000 Australian Tall Girls Newsletter.
She says she did not realize that she had been given DES until she was well into my thirties. It was only after a miscarriage and the premature stillbirth of twin daughters, that Chris learned she was a DES daughter. And, while reading up on the DES given to her mother she came across the word Stilbestrol.
"I suddenly felt ill," she said, "Stilbestrol was the name of the drug I had been given as a teenager for five years to prevent me from growing too tall."
"So not only had I been exposed in utero to the effects of DES," she wrote, "but I had received large doses of this drug as a teenager."
According to Chris, her parents got worried when she grew four inches in the eighth grade and took her to the family doctor who then prescribed the drug in 1964. While on DES, she experienced vomiting several times a day and says her breasts would leak.
During her first year in college it was determined that she was diabetic and was put on oral medication for diabetes. In my second year of college she came down with mononucleosis and was hospitalized.
Chris says that members of the staff at the hospital were completely confused about the strange drugs she was taking. "They told me I was not diabetic and that the drug given me for that was harmful," she wrote.
They also contacted her doctor about the Stilbestrol and after recovering from mono, she says, "my mother decided maybe it was time to stop all the drugs," she recalls.
But Chris soon found out that going off Stilbestrol was not so easy. "I couldn't sleep and when I did I had terrible nightmares," she says, "I bled so voluminously that I needed a D & C."
She was able to have one child, but has had "endless gynaecological problems and no way of knowing which DES exposure caused what," she says.
"Bit by bit," she wrote, "parts of my reproductive tract have become diseased and been removed."
"I've suffered from depression on and off for years," she states, "and have always wondered how much of that was due to the five years of Stilbestrol."
Chris used to think that she was alone but now "I know there are a number of us who were stupidly experimented upon by," she says, "in my case, someone who really had no idea what he was doing."
And for all this, Chris still grew to be nearly 6 feet tall.
It is also now known, that many people may have unwittingly consumed DES as late as 1999, because according to the February 2000, DES Action USA Newsletter, DES was found in US beef exported to Switzerland that year.
"Its use in cattle was finally banned in 1980," the newsletter states, "but this has not deterred some unscrupulous cattle producers from once again exposing the public to this toxic substance."
"Ironically," it states, "it took a foreign country the more cautious Swiss to uncover this use in the United States."
DES Action USA immediately called on the FDA and the USDA to not only sanction the offenders but to also enact more stringent controls to protect the public.
"We are alarmed that consumers are only learning about this now," the group noted, "when the tainted beef was discovered in July, 1999."
"We wonder," DES Action stated, "if McDonald's, Burger King, and other major burger outlets are taking steps to protect their customers from DES."
"Given the poor state of beef inspection in this country," the newsletter said, "there is no way of knowing the extent of exposure to DES for American and international consumers, particularly since the USDA has not tested beef for DES since 1991."
According to the newsletter, the source of the DES-contaminated beef was the fourth-largest meatpacker in the US. "Clearly," the group warned, "the USDA must immediately resume and expand testing for DES, and do whatever is necessary to rid our food supply of this deadly carcinogen."
The risks of cancer associated with DES have been reported for years. A study published in the June 15, 2000, New England Journal of Medicine, conducted at the Netherlands Cancer Institute, analyzed questions answered by 5,421 DES daughters, with a median age of 30 (19-45), registered with the DES Information Center
The researches found a total of 111 cases of cervical cancer were reported by 105 women (clear-cell cancer cases were excluded), which amounted to triple the risk found in non-exposed women in the same age group.
The study authors wrote, "DES daughters might actually be expected to have a lower prevalence of invasive cervical cancer than women in the general population, since DES daughters are screened more intensively for cervical cancer and since precursor lesions detected on screening are usually treated aggressively."
"Our finding," they said, "is therefore particularly striking.
Experts say this report underscores the need for DES daughters to have special DES exams at least once a year for the rest of their lives.
Back in September 2002, research published in the journal, Cancer Causes and Control, reported that DES daughters over the age of 40 were at greater risk for breast cancer.
In the study conducted by the National Cancer Institute, researchers looked at 5,000 women known to have been exposed to DES in the womb, and compared their medical histories with a similar number of women who were not exposed to the drug.
Overall, the study determined that DES daughters had an increased risk of breast cancer of 40%, but for those women over the age of 40, the increased risk was 250%, and the calculations were predicted to change as more women reached the over-40 age group.
DES daughter, Heather Justice, from the DES Action group in the UK, told BBC News on September 30, 2002: "Women who are worried about this need to ask their mothers - if they can - whether they took anything either during pregnancy or just before."
"If they did," she said, "they should arrange to see their GP and ask for breast screening."
According to the article, Heather herself survived vaginal cancer at the age of 25, and is now worried about the breast cancer risk.
In the latest study on the risks of breast cancer, published in the journal, Cancer Epidemiology, Biomarkers and Prevention, researchers at Boston University School of Public Medicine, followed 4,817 women over the age of 40, who were known to have been exposed to DES in the womb and compared them with 2,073 women in the same age group who were not exposed to the drug. All total, there were 102 cases of breast cancer in the combined groups.
The study determined that the women who were exposed to DES had a 1.9 times greater risk of developing breast cancer when compared to women in the unexposed group.
The researchers say the explanation may be that the hormone drug increases the number of breast tissue stem cells available at birth which can become cancerous.
The study's lead author, Professor Julie Palmer, stated in BBC News on August 7, 2006: "This is really unwelcome news because so many women worldwide were pre-natally exposed to DES, and these women are just now approaching the age at which breast cancer becomes more common."
She urged women who were exposed to DES to have regular breast check-ups, and to think twice about using hormone replacement therapy. "It might be wise for exposed women to avoid such supplements," she said.
"Use of hormone supplements is, in itself, an independent breast cancer risk factor," she warned, "and women may choose not to compound their already increased risk."
Dr Sarah Rawlings, of Breakthrough Breast Cancer, told BBC News, "The link between women who took DES during pregnancy and their daughters potentially having a higher risk of breast cancer is very concerning."
"If women are worried about this information," she said, "we would advise them to speak to their doctor who will be able to assess their risk."
On August 8, 2006, Heather Justice told the Daily Mail, "We've known since the Seventies about the risk of vaginal cancer, and now, as these women are getting to the menopause and there are hormonal changes, we are seeing breast cancers starting to emerge."
Heather's mother took DES for only five weeks during her pregnancy.
There have also been reports of adverse events occurring in male children. DES sons were found to have low sperm counts and undescended testicles, and it is thought they may be at an increased risk of testicular cancer, according to the August 7, 2006 Daily Mail.
In addition, the March 30, 2001, medical journal, Lancet, reported an increased risk of hypospadias in the sons of DES daughters.
READ MORE LEGAL NEWS
The article notes that the risk of hypospadias is small but that this was the first study reporting a third generation adverse effect of DES in humans and says that continued close surveillance of DES daughters, sons, and grandchildren is necessary.
Experts say, the long-term side effects of DES surfacing some 30 years after the drug was discontinued, should serve as a potent reminder of the potential harmful consequences of over-zealous drug promotion and distribution.