Frequently Asked Questions and Answers

The following are general questions and answers about DES and include those questions asked most frequently of the Center Coordinators during the follow-up studies. Answers to other questions about DES can be found on the following web sites:

This information is not meant to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider.

What is DES?

DES (diethylstilbestrol) is a synthetic form of estrogen, a female hormone. It was prescribed between 1938 and 1971 to help women with certain complications of pregnancy. Use of DES declined in the 1960s after studies showed that it is not effective in preventing pregnancy complications. When given during the first 5 months of a pregnancy, DES can interfere with the development of the reproductive system in a fetus. For this reason, although DES and other estrogens may be prescribed for some medical problems, they are no longer used during pregnancy.

What are the cancer rates for persons who have been exposed to DES in utero?

In 1971, a strong association between DES use in pregnancy and the occurrence of vaginal clear cell adenocarcinoma (CCA) in exposed daughters was reported. A study published in 1998 found that DES daughters showed no increase in risk of cancer overall or for specific types of cancer, except CCA. The daughters in this study were, however, on average, in their late 30s and had not reached the age at which we expect cancer to occur so we are continuing to monitor these women. Overall, men exposed to DES in utero have not been found to have an increased risk of cancer. The risk for specific types of cancer in men, such as testicular or prostate cancer, is unclear and we are continuing to study it.

Does DES cause infertility?

A study published in 2001, based on the National Cooperative Diethylstlbestrol Adenosis Study (DESAD) and another cohort of DES exposed and unexposed daughters, found that DES daughters were more likely to have had premature births, miscarriages, and ectopic pregnancies. In addition, the study indicated that the risk of infertility was higher in DES daughters than in unexposed women, and that the increased risk of infertility was mainly due to uterine or tubal problems. A comprehensive review of the health outcomes of DES exposed daughters published in October 2011 reports that exposed daughters were 2.37 times as likely as unexposed women to have infertility, and that exposed women who became pregnant at least once were 1.64 times as likely to have spontaneous abortion and 4.68 times as likely to have a preterm birth. These adverse events are common in the general population, and even more likely among exposed daughters.

Does DES cause early menopause?

Researchers have found that daughters whose mothers were given DES during pregnancy are two times more likely to have menopause prior to age 45, compared to women who were not exposed to DES. They estimate that 3% of DES-exposed women have experienced early menopause due to their exposure to DES.

Should I use hormone therapy if I have been exposed to DES in utero? Is it safe?

Each woman should discuss this important question with her doctor. Although studies have not shown that the use of birth control pills or hormone replacement therapy is unsafe for DES-exposed daughters, some doctors believe these women should avoid these medications because they contain estrogen.

Does DES exposure cause autoimmune diseases like Hashimoto’s thyroiditis, lupus, rheumatoid arthritis, or multiple sclerosis?

We studied autoimmune disease in depth and published our findings in 2010. They are summarized in the 2010 DES newsletter. In short, we observed no differences in overall autoimmune disease rates between women who were and were not DES-exposed. There was also no difference in lupus and optic neurosis rates between the two groups. With regard to rheumatoid arthritis (RA), our study corroborated findings of an earlier study and we observed a possible increase in RA among DES-exposed women but this was confined to women under the age of 45. There was no overall increase in RA between exposed and unexposed women. There were too few cases if idiopathic thrombocytopenia purpura (ITP) to determine whether or not it is elevated among DES-exposed women. In addition, there was no significant difference in multiple sclerosis rates between women who and were not DES-exposed. This was based on a preliminary review of early data from the DES Follow-up Study. As a result, it was not studied as extensively as the other four aforementioned autoimmune diseases.

I am having heart trouble and want to know if this may have been caused by DES?

We recently published findings for cardiovascular disease risk in the Combined DES Cohort Follow-up Study participants. We followed participantsí health outcomes through questionnaire responses and medical records, when available, from 1994 to 2013. Our analyses show a slight increase in risk of coronary artery disease and myocardial infarction among women who were prenatally exposed to DES, independent of other established cardiovascular risk factors. We did not find any increased risk of stroke, however.

Can exposure to DES before birth influence psychosexual characteristics of those individuals who were exposed?

A study published in 2003 found little support for the hypothesis that in utero exposure to DES influences the psychosexual characteristics (the likelihood of ever having been married, age at first intercourse, number of sexual partners, and having had a same-sex sexual partner in adulthood) of adult men and women.

Are there any problems with the grandchildren of women who were given DES while pregnant? (i.e., the third generation)

Several reports have examined DES grandchildren for possible abnormalities. For the granddaughters, these studies indicate that the age of first menstruation is not affected by DES, but that DES-exposed granddaughters have a greater likelihood of menstrual irregularity. In a small clinical study that included pelvic exams, researchers found no evidence of DES-related changes in the granddaughters of women given DES during pregnancy. A study of cancer outcomes in the granddaughters and grandsons showed no overall increased risk of cancer in either gender. An excess of ovarian cancer was seen in the granddaughters of exposed women, but the number of cases was small, so the evidence is considered preliminary. Investigations in Holland and France have shown a higher risk of hypospadias (a genitourinary anomaly) in the grandsons of DES-exposed women, but DES exposure was not verified in these studies. An analysis of NCI data suggested an increased risk of hypospadias in DES-exposed grandsons, but the finding was not conclusive. A study conducted in Holland found an increased risk of tracheo-esophageal fistula in granddaughters, but this also was not seen in the NCI data.

Are there any problems with the grandsons of women who were given DES during pregnancy? (i.e., the third generation)

As noted above, several studies have noted possible increased risk of hypospadius in grandsons of women who took DES during their pregnancy. However most of the studies had methodological limitations and the association was inconclusive in the NCI data, where DES exposure was verified.

My mother took DES with my sibling, but I am the one who is having all the problems. Do you know if there is any relationship between my mother taking DES before she was pregnant with me and all the problems that I am having?

At this time, we have no reason to expect that unexposed siblings of individuals who were exposed to DES in utero would experience any adverse effects because there is no biological evidence that this is possible.

I am not exposed: why do you keep contacting me since it was my sister or brother who was exposed to DES?

To determine how DES affects health, we compare two groups of people: those who were exposed to DES and those who were not exposed. Thus, even if you were not exposed to DES, your contribution to this study is vital.

What steps do I take to find out if I am a DES daughter?

It has been estimated that 5 to 10 million people were exposed to DES during pregnancy. Many of these people are not aware that they were exposed. A woman who was pregnant between 1938 and 1971 and had problems or a history of problems during pregnancy may have been given DES or a similar drug. Women who think they used a hormone such as DES during pregnancy, or people who think that their mother used DES during pregnancy, can contact the attending physician or the hospital where the delivery took place to request a review of the medical records. If any pills were taken during pregnancy, obstetrical records should be checked to determine the name of the drug. Mothers and children have a right to this information.
However, finding medical records after a long period of time can be difficult. If the doctor has retired or died, another doctor may have taken over the practice, as well as the records. The county medical society or health department may know where the records have been stored. Some pharmacies keep records for a long time and can be contacted regarding prescription dispensing information. Military medical records are kept for 25 years. In many cases, however, it may be impossible to determine whether DES was used.

I was exposed to DES before birth. How often should I have a colposcopic examination?

When we first began our DES studies, we suggested that a colposcopic examination be done each year. After several years it became obvious that only those women who had changes in the lining of the vagina or cervix (about 30%) needed to have the procedure every year. However, you should continue to have pelvic examinations and PAP smears on a yearly basis. If you have had an abnormal pap smear in the past, or have one at any time, you should follow your physician’s advice. Your gynecologist should be able to provide information on whether you have had previous vaginal epithelial changes if you are unsure of your previous history.

The questionnaires often ask for information about health habits and other information that has nothing to do with cancer. Why is the information important?

While cancer is the primary focus of the DES Follow-up Study, we also are interested to find out if DES is associated with any other types of illness. Your answers to these questions may help us make that determination.

Is any of the information collected during the questionnaire surveys available to a third party, such as an insurance company or an employer?

Historically, the data and personal information collected through this research effort has been kept confidential. Only study personnel at the local study center have access to names and addresses. This information is kept separate from the surveys and used only for contacting participants. Only data that does not contain any information that would identify the study subject is sent to the National Cancer Institute and their data management contractor for analysis. New Federal privacy laws (HIPAA) have mandated that this be continued. In addition, all of the study centers have committees created to protect people that are involved in research, called institutional review boards (IRBs). The DES Follow-up Study requires an annual review by each of these boards to reevaluate all study procedures used to safeguard issues of privacy and confidentiality.

How do I know which Center to contact?

If you are a study participant and want to contact the center from whom you have been receiving questionnaires, newsletters and other mailings, you will find the contact information for the centers on the Contact page. After you have reviewed the list of centers if you are still not sure which center to contact, choose the center that is closest to you. The contact person there will be able to assist you.