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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. Prenatally 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 and is now completed. We want to thank all the exposed and unexposed participants who returned their questionnaires. Your continued participation has allowed the investigators and scientists to continue exploring how DES has impacted health outcomes.

The NCI is currently working to move to central administration of the study with our partners at Westat, Inc. and the collaboration of our colleagues at the universities and institutions that have supervised the original cohorts. We hope to combine the data for future follow-ups to improve efficiency. For the next round of follow-up, we will be collecting information from national registries.


Latest Study Results

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

We have recently published information on the association of prenatal DES exposure with:

  • cancer (read full article here)
  • other medical conditions (read full article here), including cardiovascular disease, in men and women (read full article here)
  • depression (read full article here)
  • sexual orientation and gender identity (read full article here)
  • health outcomes in the granddaughters (read full article here)

In addition, we are continuing to study new information on prenatal DES exposure and

  • cervical abnormalities
  • benign breast disease
  • from the Third Generation Study (the granddaughters study), the health effects among women whose mothers were exposed to DES in utero
  • from the pilot study described below, DNA methylation patterns

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 epigenetic markers (changes to the genes) 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, NCI researchers was planning 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, but the pandemic put this on hold.