Diethylstilbestrol (DES) Update: Recommendations for the Identification and Management of DES-Exposed Individuals

Barbara Hammes, CNM, MS, Cynthia J. Laitman, PhD


J Midwifery Womens Health. 2003;48(1) 

In This Article

Abstract and Introduction


Diethylstilbestrol (DES) was etiologically linked to clear cell adenocarcinoma of the vagina in 1971. This article reviews on-going research and emerging information relevant to DES-related health risks, thereby enabling women's health care providers to maintain an evidence-based practice for their DES-exposed patients. To accomplish these goals, the Center for Disease Control and Prevention (CDC) has initiated a national education campaign. This article describes the reasons for this new initiative, the target audiences, the DES historical framework (including major studies and findings), and populations that are affected. Clinical steps for the identification and management of the DES-exposed individual and resultant implications for midwifery and women's health practices are reviewed.


Risk from exposure to diethylstilbestrol, also known as DES, was once believed to be a women's health issue of the past, encountered rarely in the daily practices of most midwives and women's health care practitioners of the 1990s. Today, the problems that are secondary to prior exposure to DES are known to be neither self-limited nor limited to exposed women only.

Although there are several estimates for the number of women who were prescribed DES during their pregnancies in the United States between 1938 when it was synthesized as the first orally active estrogen therapy and 1971 when the U.S. Food and Drug Administration contraindicated its use during pregnancy, the actual number of women affected is unknown. The estimated number of all individuals who have been exposed to DES in the United States (sons and daughters exposed in utero as well as mothers) is between 5 and 10 million.[1]

Women exposed to DES have a 25% to 30% increased risk for breast cancer.[2,3] Women who were exposed to DES in utero ("DES daughters") have higher risks for multiple reproductive tract anomalies and infertility, poor pregnancy outcomes, and an estimated risk of between 1:1000 and 1:1500 for developing clear cell adenocarcinoma of the vagina.[4] Some studies of men exposed to DES in utero ("DES sons") have shown increased rates of urogenital and sperm anomalies,[5] although fertility appears unaffected.[6] Researchers are now asking what types of cancers or problems might appear as these individuals age. Will there be an increased incidence of breast cancer or a late occurrence of clear cell adenocarcinoma as the cohort of women exposed to DES in utero enter menopause? Will the incidence of prostate or testicular cancer rise as the cohort of men exposed to DES in utero age? Moreover, because animal studies have documented the appearance of anomalies in offspring of males and females exposed prenatally to DES,[7] there is concern about third-generation effects in grandchildren of the original cohort of women who took DES during their pregnancies.[8]

Recognizing that millions of people may be at risk for adverse health effects secondary to DES exposure, fear of DES-related conditions, and uncertainty about currently unknown consequences, in 2002, the Centers for Disease Control and Prevention (CDC) in partnership with the National Cancer Institute launched a DES national education initiative: DES Update.[9] The foundation for this campaign is based on recently published National Cancer Institute-sponsored research on DES health effects and management.[2,10,11,12,13] The purpose of DES Update is to provide consumers, health care providers, and researchers with current information about the health effects of DES exposure and options for clinical management. A pilot study sponsored by National Cancer Institute and conducted between 1993 and 1996 assessed provider knowledge of DES.[14] Results confirmed that obstetricians/gynecologists have slightly more knowledge about DES than family practice physicians, internists, and general practitioners.[14] Across all health care provider groups, DES was thought to be an issue of the past. First, it is no longer prescribed to pregnant women and second, because most DES daughters are now in the 40 to 60 year age range, providers rarely see DES-related problems in their obstetric practices. Almost none of the health care providers were aware of the 1995 clinical practice recommendations specific for management of DES-exposed patients published by National Cancer Institute.[15]


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