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The DES Follow-Up Study investigates the long-term health consequences associated with exposure to diethylstilbestrol (DES). Since 1992, the National Cancer Institute, in collaboration with research centers throughout the United States has been conducting the DES Follow-Up Study of more than 21,000 mothers, daughters, and sons.

* The DES Action link is not associated with NCI.

STUDY UPDATE: Prenatal Diethylstilbestrol Exposure and High-grade Squamous Cell Neoplasia of the Lower Genital Tract

The link between prenatal DES exposure and vaginal and cervical clear cell adenocarcinoma in young women was established in the early 1970s. Parentally DES exposed women are also shown to have a two times higher risk of cervical and vaginal squamous cell neoplasia (a possible precursor to cancer) compared with unexposed women. The current analysis set out to determine whether the increased risk for squamous cell neoplasia of the vagina and cervix continued with age among the DES exposed and whether DES-exposed women should continue to receive annual Pap smears. Continue reading DES and High-grade Squamous Cell Neoplasia


Latest Follow-up Study

The sixth round of the DES Follow-up Study began in May of 2016. We want to thank all of the participants who have already returned their questionnaires. Your continued participation has allowed the investigators and scientists to continue exploring how DES has impacted your health.


Studies Underway

Thanks to your support of the DES Follow-up Study, the information you have provided, including from the most recent 2016 follow study, allows us to keep exploring the health effects of prenatal DES exposure. We are:

  • Examining the impact of prenatal DES exposure on the risk of developing:
    • cancer and other medical conditions, such as cardiovascular disease, in men and women;
    • cervical dysplasia, high breast density, benign breast disease, and breast carcinoma in situ in women; and
    • depression.

In addition, we are continuing to analyze new information from the Third Generation Study (the granddaughters study) to determine the health effects among women whose mothers were exposed to DES in utero.


Pilot Study to Collect Blood Samples in Prenatally DES Exposed and Unexposed Women [Complete]

Researchers at the National Cancer Institute and Boston University conducted a study to determine the feasibility of collecting blood samples in prenatally DES exposed and unexposed women. The purpose of the collection was to provide blood to measure genetic markers and reproductive hormone concentrations. In the small pilot study of 60 women from our long-term DES Follow-up Study (40 who were exposed to DES and 20 who were not) blood samples were drawn and sent to a laboratory for measurements. The study was completed in 2015. Results showed differences in how estrogens are metabolized between the exposed and unexposed women. The researchers thought that these differences may influence the modestly increased risk of breast cancer among exposed women (Estrogen Metabolism in Postmenopausal Women Exposed In Utero to Diethylstilbestrol. Troisi, R. et al. Cancer Epidemiol Biomarkers Prev. 2018 Oct;27(10):1208-1213.)


Expanded Study of Genetic Markers and Hormone Metabolism in DES Exposed Daughters

Building upon the pilot study of genetic markers and hormone metabolism in prenatally DES exposed and unexposed women, researchers plan to launch a larger study to further explore the effect of DES exposure on these factors. Together with scientists from Boston University and the University of Chicago, NCI researchers will begin enrolling women in late 2020.