DES pregnancy

DES, Nazis, and American Industrialists

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DES is a synthetic estrogen-like compound developed in 1938 by English chemist Charles Dodd. German chemists under the employ of the Nazis were able to synthesize DES cheaply and easily from coal tar and used it to fatten livestock. There was a problem, however. The young boys who cared for the livestock, and thus were exposed to the chemical, developed swollen and painful breasts, a condition now called gynecomastia. This would be one of many indications that perhaps the drug was not as safe as proclaimed. The German solution to avoid this side effect was to have women care for the animals because they had breasts already, after all. An American scientist in the employ of several American industrial interests and with ties to German researchers during and after the war, concurred:

A drug effect of interest in relation to industrial hygiene is that of DES, the manufacture of which only female workers are employed, because untoward effects induced in males by the absorption of this material in the course of a day’s work. Boys develop a mammary swelling with such severe pain and pressure of a shirt cannot be endured. On the discontinuance of exposure the condition subsides spontaneously within a week or two. No sequelae have been reported and no abnormalities of the testes have been seen. On the other hand, older males develop some atrophy of the testes and some apparently temporary loss of sexual potency. This condition is said to have been cured by the administration of androsterone. Exposed women had no nausea or menstrual abnormalities.” The Secret History of the War on Cancer, pp 90.

Despite the early indicator that DES might not be safe, and without any other testing beyond the basic toxicology to determine lethality, it was approved by the FDA in 1941 for vaginitis and as an early hormone replacement therapy for menopausal women. It was later approved a variety of low estrogen indications. In 1947, the FDA approved its use in pregnant women with a history of miscarriage. DES had been used off-label for miscarriage prevention since the early 1940s, despite the fact that little evidence supported its use and animal studies indicated clear carcinogenic and congenital reproductive abnormalities in the offspring. Indeed, years before the development of DES, the relationship between synthetic hormones and several forms of cancer, were recognized. Nevertheless, the promise of pharmaceutical industry profit overrode any potential long term consequences of the drug.

After 10 years of widespread use and marketing, a double-blind, placebo-controlled study on the efficacy of DES was finally conducted. As one might expect, it was found ineffective in preventing miscarriage. In fact, women on DES had a higher risk of miscarriage. Later studies in the 1960s began detailing the adverse effects this drug. Nevertheless, despite mounting evidence of the dangers of diethylstilbestrol, it remained on the market and widely used through the early 1970s in the US and into the 1980s in some European countries. In the US alone, it is estimated that some 5-10 million women and their children were exposed to DES. Because the compound was never patented, 287 drug companies sold DES under a multitude of brands  and for an array of low-estrogen conditions.

Two decades after both the Germans and the English recognized that DES caused gynecomastia in the male farm hands, US reports of gynecomastia and sterility in US poultry workers were evident. As a result, the FDA banned it for use in poultry under the newly enacted Delaney Clause to the FDA 1958. It would be another 13 years before DES was banned during pregnancy and 20 years before DES was banned in cattle. That means that neither the evidence that DES was ineffective in the prevention of miscarriage but may actually increase risk, nor the evidence of congenital abnormalities and cross-generation cancer risks were sufficiently troubling to initiate its ban. DES was finally banned for use in cattle until 1979. It would be years after before it was removed from the food chain (if it even is now). “In 1980, half a million cattle from one hundred and fifty-six feedlots in eighteen states were found with illegal DES implants.” Even upon FDA’s decision to withdraw its approval of DES in cattle and feed, it did so on grounds of the procedural non-compliance of the manufacturers, while simultaneously maintaining the safety of DES, “because there is no evidence of a public health hazard.” Even now, despite its clear carcinogenic and teratogenic risks, it is still used in veterinary care.

DES represents just one of many pharmaceuticals marketed as safe upon the flimsiest of measures. It was a known carcinogen before its approval. By 1939, 40 papers had been published detailing its carcinogenic activity. Unfortunately, they were countered heavily by industrial interests with some 257 papers published within the proceeding two years touting its benefits. As is the case today, the influence of advertising to skew public opinion, whether the medical public or lay public, was intense and ultimately successful. Even though the evidence suggesting DES prevented miscarriage was highly controvertible, it was approved by the FDA and adopted wholeheartedly by the medical industry. Even when it was proven ineffective at preventing miscarriage in 1953, it was still prescribed regularly.

“…doctors continued to widely prescribe DES in normal pregnancies like ‘vitamins’ or ‘a little extra insurance.’ They continued because of the highly aggressive sales tactics of pharmaceutical representatives and because it was widely advertised in medical journals and the popular press. Influenced by the advertisements, and in their desperate desire to avoid miscarriages, women demanded DES.”

It was not until 1971, that the FDA finally recognized the risks. DES, like thalidomide, DDT, and other chemicals developed during this period, are often viewed through the lens of history as representative of a bygone era, when science and technology were yet nascent endeavors. I would argue that is incorrect. While it is true that science and technology have advanced significantly in recent decades, what remains steadfast are the cultural and monetary conflicts that motivate and define what is accepted as true in this field; and sadly, what is accepted as true is whatever industry tells us.

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Chandler Marrs MS, MA, PhD spent the last dozen years in women’s health research with a focus on steroid neuroendocrinology and mental health. She has published and presented several articles on her findings. As a graduate student, she founded and directed the UNLV Maternal Health Lab, mentoring dozens of students while directing clinical and Internet-based research. Post graduate, she continued at UNLV as an adjunct faculty member, teaching advanced undergraduate psychopharmacology and health psychology (stress endocrinology). Dr. Marrs received her BA in philosophy from the University of Redlands; MS in Clinical Psychology from California Lutheran University; and, MA and PhD in Experimental Psychology/ Neuroendocrinology from the University of Nevada, Las Vegas.


  1. Is there an upper limit for thiamin supplementation while breastfeeding? (Thiamine hcl pills)
    My mood and energy seems stable only at 300 to 500 mg per day. Even though now I eat only whole foods (incl lots of animal fat and protein), I need that dose.
    I have many health conditions going back to childhood, grew up eating processed junk food 3 meals a day, but wonder if I can take thiamin while breastfeeding my baby.
    Thank you.

    • Jane, I think you meant to place this comment on one of Dr. Lonsdale’s posts. To answer your question though, no, this is no upper limit, within reason of course. Many folks take very high doses. It is entirely contingent on your individual circumstances, genetics, needs, etc.

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