Overview of DES
Diethylstilbestrol (DES), a synthetic estrogen, was prescribed to millions of pregnant women in the United States from 1938 to 1971. Manufactured under many different names (see DES Names), the drug was marketed to prevent miscarriage or premature birth by supplementing a pregnant woman's natural estrogen production. Research noted that a decrease in urinary estrogen and progesterone preceded adverse pregnancy outcomes. Thus it was postulated that administering estrogen would induce placental hormone production; therefore, sustaining a viable pregnancy (Smith, et al. 1948). Despite a landmark study in the early 1950s finding DES ineffective in preventing miscarriage and premature birth (Dieckmann, et al. 1953) and subsequent research showing harm to the developing fetus, it was not until 1971 that the Food and Drug Administration issued a warning about the damaging effects of DES. In the United States, it is estimated that between 5 and 10 million people were exposed to DES during the years it was prescribed. DES was similarly prescribed in several European countries from the 1950s into the 1970s and may still be used in developing countries.
Although DES is no longer prescribed to pregnant women in the United States, DES exposure continues to affect many lives:
DES is associated with a number of adverse health effects; some of those health effects, including third-generation effects, are still unknown. Research to date suggests that health risks for daughters born to DES mothers include:
- Increased risk of clear cell adenocarcinoma (CCA), a rare form of vaginal cancer
- Structural differences in reproductive anatomy
- Increased risk of intraepithelial dysplasia and neoplasia
- Increased risk of infertility
- Increased risk of pregnancy complications
DES mothers, or women prescribed DES, appear to have a slightly increased risk of breast cancer. DES sons—boys exposed to DES in utero—have an increased risk of being born with genital abnormalities.
Identification of Individuals Exposed to DES
Today, clinicians may still encounter patients who are DES-exposed. It is difficult to identify and confirm DES exposure in an individual. No simple test can be given. There have been limited efforts to contact and subsequently monitor the health of those exposed to DES, but researchers have been unable to identify everyone. Many women and their children do not know whether they were exposed to DES, and DES-related cancers often take many years to develop and appear.
The ideal, but not always practical, way to identify DES exposed individuals is to review complete obstetrical, hospital, or pharmacy records. This method can identify mothers who have forgotten that they received DES or daughters whose gynecologic examinations reveal no changes. However, in many cases, old records have been destroyed or are incomplete; antenatal medications are not always mentioned in hospital obstetrical records; and mothers of exposed children cannot always be contacted.
Educational materials displayed in waiting rooms can alert individuals about DES, but more important, clinicians need to ask pointed questions while taking patients’ medical histories. Patients may not volunteer information about DES exposure. Questions to ask patients include:
Did you or your mother:
- Take DES during pregnancy?
- Have problems carrying a pregnancy to term?
- Have a history of miscarriages for which medication was prescribed?
- Have a history of ectopic pregnancy?
Smith, O.W., et al. (1999) Diethylstilbestrol in the prevention and treatment of complications of pregnancy. 1948. Am J Obstet Gynecol. 1999 Dec;181(6):1570-1.
Dieckmann, W. J., et al. (1953). Does the administration of diethylstilbestrol during pregnancy have therapeutic value? American Journal of Obstetrics and Gynecology, 66, 1062–1081.
|Clinician Information: DES Daughters - Women Exposed in Utero|
|Clinician Information: DES Mothers - Women Prescribed DES|
|Clinician Information: DES Sons - Men Exposed in Utero|