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What is DES?


Known as Diethylstilboestrol worldwide and better known as Stilboestrol in Ireland and the UK, DES is a powerful synthetic oestrogen, which was given to women all over the world to prevent miscarriage between 1949 and 1975, even though some reports as early as 1953 showed that it was not effective for this purpose.

However worse than just being ineffective, DES turned out to be a teratogen — an agent that can cause malformations of an embryo or foetus. The dosage of oestrogen in DES exposed both mothers and their unborn children to extremely high doses of synthetic oestrogen. Subsequent studies found that exposure to synthetic oestrogen during critical stages of child development in the uterus can increase the risk of abnormalities. It can cause structural long-term pathological changes resulting in cancer.

No wonder then that DES has come to be known as the silent thalidomide.

DES was sold under many brand names and was given by injection, pill and vaginal suppository (sometimes called pessaries) and for varying lengths of time. Use of DES varied, for example, some women received a daily dose throughout pregnancy while others  received weekly injections.

In the United States, an estimated 5–10 million people were exposed to DES, in Australia an estimate 740,000 people, in the UK approximately 300,000 and the numbers for Ireland are unknown. Estimated numbers for other countries are contained in the links at the end of this article. Exposed means women who were prescribed DES while pregnant, and the children born of those pregnancies, known as the DES daughters and sons.

The United States Food and Drug Administration (FDA) notified physicians in 1971 that DES should not be prescribed to pregnant women. However though the FDA ban applied in the US, DES continued to be prescribed in many European countries until the late 1970s.

Now researchers are investigating whether DES health issues are extending into the next generation, the so-called DES Grandchildren. As study results come in, there is growing evidence that this group has been adversely impacted by a drug prescribed to their grandmothers.

The Consequences

More than half of DES daughters have adenosis, a type of cell tissue in the vagina of cervix which is not usually found there. Adenosis is harmless but can cause discharge.

In 1971 it was discovered that DES could cause a rare form of vaginal cancer (clear cell adenocarcinoma) in young women whose mothers had been given the drug during pregnancy. About 1 in 1000 DES daughters will develop this cancer, which is curable when detected early.

Up to half of DES daughters will have pregnancy problems including tubal pregnancy, miscarriage and premature labour and delivery. Many DES daughters have malformations of the cervix, uterus and Fallopian tubes caused by DES and these are probably the cause of pregnancy complications. However, 80% of DES daughters do have a successful pregnancy at some stage.

Some studies have shown genital problems in DES sons. For more on this see the article here on DES Sons.

DES mothers are at somewhat higher risk of breast cancer and should be cautious about using HRT. In addition further studies have shown that DES daughters are at an increased risk of breast cancer.

Because of their cancer risk, DES daughters must have a special screening examination by a doctor trained in the techniques to detect this form of cervical and vaginal cancer as well as regular breast exams.

A study published in the British journal of obstetrics and gynaecology in November 1983  found that “psychiatric disease (especially depression and anxiety) was reported by general practitioners about twice as often in the treated group offspring (sons and daughters) as in the untreated group. This result cannot be due to bias, and is unlikely to be due to confounding or chance, and may thus represent an adverse effect of exposure to stilboestrol in utero.”

A DES Follow-up Study by the US National Cancer Institute began in 1992 and included over 6,500 women (4,600 exposed and 1,900 unexposed). The results were released in 2011 and researchers found that the daughters with exposure to DES while in the womb had an increased risk of 12 medical conditions, including a twofold higher risk of infertility and a fivefold increased risk of having a preterm delivery.

This study is also the first to estimate the cumulative proportion of all DES-exposed women who developed these conditions because of their exposure. Of all DES-exposed women, 1 in 5 will experience some level of infertility because of their exposure. And of all those exposed women who are successful in having at least one birth, 1 in 3 will have a preterm delivery due to DES.

Although DES-exposed daughters have about 40 times the risk of developing CCA than unexposed women, CCA is still a rare disease, occurring in 1 in 1,000 DES-exposed daughters. While the first women diagnosed with this condition in the late 1960s were adolescents and young adults at the time of their diagnosis, the research now shows that the risk for DES-exposed daughters continues through at least age 40. In addition, these women are more than twice as likely to develop pre-cancerous cells in the cervix or vagina (called cervical intraepithelial neoplasia) and have an 80 percent higher chance of developing breast cancer after age 40. According to the results of this study, by age 55, 1 in 25 DES-exposed daughters will develop abnormal cellular changes in the cervix or vagina, and 1 in 50 will develop breast cancer due to their DES exposure.

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For more information about DES exposure and cancer risk, please go to

Actions to take

  • First of all remember that although these studies are showing a risk, the risk is still statistically small and these are still rare cancers.
  • Stay healthy and avoid unnecessary health risks. A positive mental attitude is important for all aspects of health and as anxiety and depression can be a consequence of DES exposure, if you suffer from these conditions look at the Wellbeing section of this site and other sources for ways to develop a healthier and more positive mindset.
  • Using the contraceptive pill or HRT may not be advisable as it  exposes your body to more oestrogen. Discuss this carefully with your doctor.
  • Tell your doctor if you have been exposed to DES and ensure that they know what regular health checks should be performed and also ensure that they know how to perform these checks or who they should refer you to for proper monitoring if they don’t feel equipped to monitor you themselves.
  • Take care of your vagina and cervix. Practise safe sex and try to minimise exposure to the HPV virus. Rough or very vigorous sexual intercourse should be avoided as increased friction can irritate the sensitive vaginal lining and, if HPV is present, cause it to embed more deeply in the cervix.
  • Don’t smoke.
  • Regular pelvic and breast exams and Pap tests are essential. Depending on where you live, Pap smears may be done at six-monthly or yearly intervals. They should be carried out at a minimum annually.
  • According to the NCI fact sheet:

A thorough examination may include the following:

Pelvic examination

Pap test and colposcopy—A routine cervical Pap test is not adequate for DES daughters. The Pap test must gather cells from the cervix and the vagina. It is also good for a clinician to see the cervix and vaginal walls. They may use a colposcope to follow-up if there are any abnormal findings.


Breast examinations—It is recommended that DES daughters continue to rigorously follow the routine breast cancer screening recommendations for their age group. The NCI fact sheet Mammograms includes information about these guidelines.


For more information on DES please see these links:

Facebook DES Group:


DES UK – Journal of a DES Daughter


Des Action USA
P.O. Box 7296
Jupiter, FL 33468

DES Sons Network
Michael Freilick | 104 Sleepy Hollow Place | Cherry Hill, NJ 08003

DES 3rd Generation Network
Box 21 | Mahwah, NJ 07430 | e-mail



DES Action Australia, Inc.
PO Box 282
Camberwell 3124 Vic. Australia

DES Action Australia – NSW  
14 Edmundson Close
Thornleigh NSW 2120 Australia



Reseau DES France
12 rue Martinon
40000 Mont de Marsan


The Netherlands

DES Centrum
Wilhilminapark 25
3581 NE Utrecht
The Netherlands