The Rise and Fall of Diethylstilbestrol in Human Medicine
Diethylstilbestrol (DES) was first synthesized in 1938 and quickly became a commercially available drug for a wide range of applications. As a potent nonsteroidal estrogen, it was used to treat menopausal symptoms, lactation suppression, and a variety of other hormone-related conditions. However, its most widespread use—and the source of its infamy—was its prescription to pregnant women from the 1940s to 1970s. Despite early studies questioning its effectiveness, it was heavily marketed and promoted to prevent miscarriage and other pregnancy complications.
The medical community's reliance on DES came crashing down in 1971 with a groundbreaking study published in the New England Journal of Medicine. It linked in utero DES exposure to a rare vaginal and cervical cancer, clear-cell adenocarcinoma, in young women. This discovery prompted the US Food and Drug Administration (FDA) to advise against prescribing DES during pregnancy, though it was not officially banned for human use for some time. Later, the FDA fully withdrew approval for human use of DES products containing more than 25mg per unit dose.
The Lingering Legacy of DES Exposure
For the millions of people exposed to DES, the drug’s story did not end with its removal from the pregnancy market. The health consequences for mothers, daughters, and sons who were exposed in utero have been profound and long-lasting. A vast network of research, spearheaded by organizations like the National Cancer Institute, has tracked these adverse outcomes for decades. The health issues associated with DES exposure include:
- For mothers: An increased risk of breast cancer.
- For daughters (in utero exposure): Increased risk of clear-cell adenocarcinoma of the cervix and vagina, structural changes to the reproductive organs (e.g., T-shaped uterus), infertility, ectopic pregnancies, and preterm deliveries.
- For sons (in utero exposure): Testicular abnormalities such as undescended testes, testicular cancer, and reduced fertility.
- For grandchildren: Emerging evidence suggests potential multigenerational effects. Research has shown an increased risk of attention-deficit/hyperactivity disorder (ADHD) in the grandchildren of women who took DES. This demonstrates how endocrine disruptors like DES can have effects that persist across generations, impacting health in unexpected ways.
What Is DES Used for Now? (The Short Answer)
Following the widespread recognition of its severe and intergenerational risks, DES was phased out of most human applications. Today, it is effectively abandoned for treating any condition in humans due to the availability of safer, more effective alternatives. However, DES is not completely gone. Its primary remaining medical use is in veterinary medicine.
Specifically, it is used to treat urinary incontinence in spayed female dogs. This is a targeted application where its potent estrogenic effects can help with bladder sphincter control. The drug is administered at very low doses and under strict veterinary supervision to mitigate potential side effects.
DES Use in Veterinary Medicine: A Historical and Current Comparison
| Aspect | Historical Use in Humans (1940s-1970s) | Current Use in Veterinary Medicine (Dogs) |
|---|---|---|
| Indication | Pregnancy complications (miscarriage prevention), menopausal symptoms, postpartum lactation suppression, prostate/breast cancer | Urinary incontinence in spayed female dogs |
| Dosage | Highly variable, often very high, with potentially toxic total exposures | Very low, carefully controlled, and veterinarian-supervised |
| Risks | Severe, proven risks including increased cancer rates and reproductive issues in mothers and offspring | Lower due to controlled dosage and different physiological context, but side effects are possible |
| Regulation | FDA initially approved, later issued warnings and eventually withdrew approval for human use | Regulated for veterinary applications, with no human use allowed |
| Availability | Widely available under many brand names | Limited and specific to veterinary prescriptions |
A Landmark in Endocrine Disruption Research
DES holds a significant place in the history of pharmacology and public health as a landmark example of an endocrine-disrupting chemical (EDC). EDCs are exogenous agents that interfere with the endocrine system, causing adverse health effects in an organism or its progeny. The DES experience brought international attention to the devastating consequences of fetal exposure to potent endocrine disruptors, paving the way for further research and greater regulatory scrutiny of pharmaceuticals and environmental chemicals. The scientific community now understands that exposure to these substances during sensitive developmental periods can have lifelong and even transgenerational impacts.
Conclusion
The answer to what is DES used for now? is a testament to the evolution of medical knowledge and the importance of rigorous, long-term drug safety testing. No longer a part of human medicine, DES exists as a cautionary tale of a drug with catastrophic long-term effects. Its legacy continues to affect generations of individuals and serves as a powerful reminder of the lasting impact of pharmaceuticals and the importance of understanding the full scope of a drug's pharmacological profile before widespread use. The drug's limited, carefully controlled application in veterinary medicine for canine urinary incontinence is the only legitimate medical use that remains, highlighting the stark contrast between its dangerous human history and its specific, low-risk role today.
Learn More About DES's Legacy
For more information on the history and health effects of DES, consult resources such as the National Cancer Institute's fact sheet.
