DES side effects in the third generation, known in 2005

image of DES russian dolls

The history of DES, lessons to be learned

“Health care professionals have to know the (full) history of DES to prevent future disasters with drugs prescribed.”

Abstract – 2005

At this moment, little is known about the implications of DES exposure for the third generation. Research has been done in mice to investigate the possibility of negative effects of DES on the male offspring of in utero exposed mice. The fertility of these males appeared to be the same as the fertility of the reference group. However, an increase in lesions of the testis and in tumours of the reproductive tract was reported, thereby providing the suggestion that effects of DES exposure can be transmitted to the third generation in mice.

Female offspring of mice exposed to DES in utero was also examined. In a group of 40 third generation mice ten uterine adenocarcinomas and five ovarian cystadenocarcinomas were seen, while tumours were absent in the control group. The development of these forms of cancer seemed to be age-dependent.

To find out whether these results would also be seen in humans, a group of 28 third-generation daughters was observed. While 61.5% of their mothers demonstrated cervical or vaginal changes associated with DES exposure in utero, none of these daughters showed any abnormality in the lower genital tract. However, this study is too small to draw conclusions but it seems that the carryover of DES effects in the female third generation is not of great significance.

Because the effects of DES in the third generation might be caused by biologic mechanisms, a study focused on the age at menarche in DES granddaughters. Fifty-two girls of mothers exposed to DES in utero were compared with 71 girls of unexposed mothers. The age at menarche was unaffected by DES administration to the grandmothers of these girls.

Next to the consequences in DES granddaughters, DES effects on the third-generation sons were also examined. As a result of two cases of hypospadia in sons of women that were exposed to DES in utero, a cohort study was done to find out whether an association between hypospadia in third generation males and DES exists. Hypospadia is a defect of the urogenital system in which the urethral opening is located on the ventral surface of the penis or on the scrotum. Sons of women with fertility problems (N ¼ 8934) were included in this study; 205 boys were sons of women exposed to DES in utero and the mothers of the remaining 8729 were unexposed. Four cases of hypospadia were reported in sons of exposed women compared with eight in the sons of unexposed. The prevalence rate ratio for hypospadia following from these results is 21.3, thereby suggesting an association between the administration of DES and the risk of hypospadia in the male third generation.

These outcomes suggest that there are no effects of DES exposure in females of the third generation, but that an increased risk of hypospadias exists for male offspring of women exposed to DES in utero. However, these results are obtained from small studies, so more research has to be carried out to obtain more reliable information.


  • The history of DES, lessons to be learned, Pharmacy world & science : PWS, PMID: 16096877, 2005 Jun.
  • Image credit rawdonfox.

Findings in female offspring of women exposed in utero to diethylstilbestrol

Lower genital tract abnormalities in DES granddaughters

2002 Study Abstract

To examine a group of women (third-generation daughters) whose mothers were exposed in utero to diethylstilbestrol (DES) and compare their findings on pelvic examination with those noted in their mothers.

Letters were mailed to women documented to have been exposed in utero to DES who had given birth to a female offspring, inviting them to have their daughters come in for a detailed history and pelvic examination. Records of the mothers whose daughters appeared for examination were reviewed, and findings noted at the time of their initial examination were recorded. Detailed pelvic examination of the third-generation daughters included colposcopic examination and iodine staining of the vagina and cervix and Papanicolaou smear. The findings observed in these women were compared with those noted in their mothers at the time of their mothers’ first examination.

Twenty-eight third-generation daughters were examined. Three of the daughters were delivered from one mother. Review of the mothers’ records indicated that 16 (61.5%) of the mothers exposed to DES during their pregnancy demonstrated structural changes of the cervix, upper vagina, or vaginal epithelial changes consisting of adenosis, nonstaining vaginal epithelium after application of iodine solution, or white epithelium within the vagina. None of the daughters were found to have changes usually associated with DES exposure.

The absence of abnormalities in the lower genital tract in third-generation women compared with the high frequency of these abnormalities in their mothers suggests that third-generation carryover effects of in utero DES exposure are unlikely.


  • Findings in female offspring of women exposed in utero to diethylstilbestrol, Obstetrics and gynecology, PMID: 11814496, 2002 Feb.
  • 3D Animal Models featured image credit Paolo Bendandi.

Animal models of prenatal exposure to diethylstilboestrol

image of animal models

The multigeneration effect of DES provides a model to test the mechanism of transmission of cancer risk from one generation to the next

1989 Study Abstract

Animals of several species exposed perinatally to diethylstilboestrol (DES) have been evaluated for anomalies and tumours.

In male offspring, anomalies of the testis and epididymis have been reported, but evidence for tumours has been very limited.

Many anomalies and tumours have been recorded in female offspring, and some of these duplicate the anomalies and tumours reported in DES-exposed women, whereas others either have not yet been discovered or else do not occur in the human species.

A variety of abnormal physiological responses has been identified in animals exposed perinatally to DES. There were altered levels of hormones and receptors; responses to postnatal injection of hormones were often modified; and an increased susceptibility to other carcinogens has been established.

Several mechanisms have been postulated to explain tumour production later in life after perinatal exposure to DES. Deficiencies in immune function indicate a mechanism of impaired immune surveillance. The presence of DES and its metabolites in the fetus and neonate raise the issue of somatic mutation. Evidence for sister chromatid exchange, cell transformation in tissue culture and other toxic effects on chromosomes support the somatic mutation hypothesis. A third hypothesis is involvement of abnormal differentiation of the hypothalamus. Structural, hormonal and behavioural changes support this idea.

Possible additional problems in humans after exposure to DES, on the basis of animal model studies, are increased tumour frequency with ageing and transmission of cancer risk to the third generation. The multigeneration effect of DES provides a model to test the mechanism of transmission of cancer risk from one generation to the next.

The outcome of such experiments could have considerable impact on the understanding of the association between DES and cancer specifically and transplacental cancer generally.


  • Animal models of prenatal exposure to diethylstilboestrol, IARC scientific publications PMID: 2680952, 1989.
  • 3D Animal Models featured image credit psionicgames.

Family History is Underestimated in Children with Isolated Hypospadias

A French Multicenter Report of 88 Families, 2018

In humans massive exposure to strong EDCs (DES) has effects through several generations and may contribute to some familial expression of hypospadias.


While familial forms of complex disorders/differences of sex development have been widely reported, data regarding isolated hypospadias are sparse and a family history is thought to be less frequent. We aimed to determine the frequency of hypospadias in families of boys with hypospadias, to establish whether these familial forms exhibit a particular phenotype and to evaluate the prevalence of genetic defects of the main candidate genes.

Materials and methods
A total of 395 boys with hypospadias were prospectively screened for a family history with a standardized questionnaire, extensive clinical description, family tree and sequencing of AR, SF1, SRD5A2 and MAMLD1.

Family history of hypospadias was more frequent than expected (88 patients, 22.3%). In 17 instances (19.3%) familial hypospadias cases were multiple. Familial hypospadias was related to the paternal side in 59.1% of cases, consisting of the father himself (30.7%) as well as paternal uncles and cousins. Premature birth, assisted reproductive techniques, other congenital abnormalities and growth retardation were not more frequent in familial hypospadias than in sporadic cases. The severity of phenotype was similar in both groups. The results of genetic analysis combined with previous data on androgen receptor sequencing revealed that familial cases more frequently tend to demonstrate genetic defects than sporadic cases (5.68% vs 1.63%, p = 0.048).

Familial forms of hypospadias are far more frequent than previously reported. Even minor and isolated forms justify a full clinical investigation of the family history. Detecting these hereditary forms may help to determine the underlying genetic defects, and may improve followup and counseling of these patients.



Harms to the third generation

Diethylstilbestrol (DES): also harms the third generation,
Prescrire international, 2016 Dec


Diethylstilbestrol(DES) is a synthet- ic nonsteroidal oestrogen and endo- crine disruptor that was used in the 1950s-1970s to prevent spontaneous abortion, despite its lack of proven efficacy.

Millions of women worldwide took DES during pregnancy. In France, between 1951 and 1981, about 160 000 children were exposed to DES during the first trimester of their intrauterine life, and in some cases almost throughout the entire pregnancy. They are referred to as “DES daughters” and “DES sons“. In 2010, in France, about 25 000 DES daughters were aged 33 to 40 years: pregnancies among these women are foreseeable until about 2020.

In utero exposure to DES can have harmful effects. In particular, DES daughters have an increased risk of cancer and structural abnormalities of the uterus that can adversely affect their pregnancies.

What are the consequences of taking DES during pregnancy for the third generation, i.e. the children of DES children? To answer this question, we reviewed the available data in mid- 2016 using the standard Prescrire methodology.

According to a retrospective study conducted in France by Réseau DES France, published in 2016, which included 4409 DES grandchildren (2228 girls and 2181 boys) and about 6000 controls, about one-quarter of DES grandchildren are born prematurely. Preterm delivery exposes neonates to serious neonatal complications, including

  • neurosensory disorders,
  • disabilities
  • and increased neonatal mortality.

The more premature the baby, the greater the risk of complications. In the Réseau DES France study, cerebral palsy was more frequent in the DES grandchildren group: 59/10 000, versus 6/10 000 in the control group.

A study conducted in the United States in about 4500 DES daughters found that preterm delivery occurred at a frequency of about 26%, much higher than that reported in controls. Neonatal mortality was 8 times higher among DES grandchildren, and the risk of stillbirth was twice as high. Other smaller studies have also shown an increased risk of preterm birth.

A cohort study conducted in about 5000 DES grandchildren found that the risk of malformations of any type was higher than in the unexposed control group.

Epidemiological studies, conducted in several countries, found an increased frequency of hypospadias in DES grandsons. The relative risk was about 5 in the largest study. Other, less robust studies found no statistically significant difference.

Several studies in several countries have shown a twofold increase in the risk of oesophageal atresia or tracheo- oesophageal fistula in DES grandchildren.

The data on congenital heart defects or musculoskeletal malformations are limited and uninformative.

Epidemiological studies have not identified a significant increase in the risk of gynaecological anomalies or cancers in DES granddaughters.

Limited data are available on the risk of malformations in the children of DES sons. The data obtained in rodents exposed to DES (and other endocrine disruptors) make it entirely plausible that in utero exposure to DES, in humans too, provokes epigenetic effects that are passed on to future generations not directly exposed to DES.

In practice, these data should be discussed with DES daughters, their partners and healthcare teams so that appropriate monitoring, clinical management and follow-up can be arranged for both mother and baby. The harms of taking DES during pregnancy last for decades and affect future generations.


  • Diethylstilbestrol (DES): also harms the third generation, Prescrire international, NCBI PubMed PMID: 30758926, 2016 Dec 25.
  • Image credit Rod Long.

Genetic variation in sensitivity to DES and breast cancer risk

Extent of variation in responses to DES among strains of rodents

2018 Study Abstract

Breast cancer risk is intimately intertwined with exposure to estrogens. While more than 160 breast cancer risk loci have been identified in humans, genetic interactions with estrogen exposure remain to be established. Strains of rodents exhibit striking differences in their responses to endogenous ovarian estrogens (primarily 17β-estradiol). Similar genetic variation has been observed for synthetic estrogen agonists (ethinyl estradiol) and environmental chemicals that mimic the actions of estrogens (xenoestrogens).

This review of literature highlights the extent of variation in responses to estrogens among strains of rodents and compiles the genetic loci underlying pathogenic effects of excessive estrogen signaling.

Genetic linkage studies have identified a total of the 35 quantitative trait loci (QTL) affecting responses to 17β-estradiol or diethylstilbestrol in five different tissues. However, the QTL appear to act in a tissue-specific manner with 9 QTL affecting the incidence or latency of mammary tumors induced by 17β-estradiol or diethylstilbestrol.

Mammary gland development during puberty is also exquisitely sensitive to the actions of endogenous estrogens. Analysis of mammary ductal growth and branching in 43 strains of inbred mice identified 20 QTL. Regions in the human genome orthologous to the mammary development QTL harbor loci associated with breast cancer risk or mammographic density.

The data demonstrate extensive genetic variation in regulation of estrogen signaling in rodent mammary tissues that alters susceptibility to tumors. Genetic variants in these pathways may identify a subset of women who are especially sensitive to either endogenous estrogens or environmental xenoestrogens and render them at increased risk of breast cancer.

Responses to DES among strains of rodents

…”Long-term exposure to diethylstilbestrol (DES) increased ductal branching to a similar extent in wild type BALB/cJ and 129/SvEv female mice but no mammary tumors were observed in either strain.” …

…”ACI rats also developed mammary tumors with chronic exposure to 17β-estradiol or DES.”…

…”While estrogen agonists induce proliferative responses in mammary, uterine and pituitary, they cause regression in other tissues. DES induced thymic regression in both C57BL/6 and BALB/c strains. Although the strains differed in initial thymus weights, both exhibited similar ~1.5 g decreases following DES treatment. In rats, the F433 strain was most responsive in pituitary and uterine tissues, but DES-induced thymic regression was greatest in the SD strain compared to F344 and BN.”…

… “In contrast, ACI rats have a persistent proliferative response to DES in mammary epithelium without a compensatory increase in apoptosis and was associated with extensive hyperplasia. Thus, strains of rodents appear to have adopted different strategies to achieve tissue homeostasis. The ability to attenuate signaling also appears to differ among tissues. An example is the formation of neoplastic lesions in the uterus of 129/SvEv mice treated with DES, but no lesions developed in the mammary glands of these mice.”…

Genetic variants determining responses to DES

…”When pituitary weight was used as a phenotypic indicator of estrogen stimulated lactotroph proliferation, five QTL were identified upon characterization of DES treated female F2 progeny generated in an intercross between F344 and BN rats. One additional QTL was mapped during characterization of backcross progeny generated using these same strains. When ACI rats were utilized as the sensitive strain, six QTL were mapped upon characterization of DES treated male F2 progeny generated in reciprocal intercrosses between ACI and COP rats…”

…”A second QTL, Eutr2 was mapped to the same region of chromosome 5 through characterization of DES treated congenic rats in which BN alleles across proximal chromosome 5 were introgressed onto the F344 genetic background.”…

…”Treatment with DES identified QTL influencing repression on chromosome 10 (Esta1) and chromosome 2 (Esta2 and Esta3) in a study using male F2 progeny from a BN x ACI intercross. QTL associated with regression of testes induced by DES were identified on chromosomes 1 and 7 in recombinant inbred male rats.”…


  • Full study (free access) : Genetic variation in sensitivity to estrogens and breast cancer risk, Mammalian genome : official journal of the International Mammalian Genome Society, NCBI PubMed PMC5936622, 2018 Feb 29.
  • Positions of QTL regulated responses to estrogens in 5 tissues in rats featured image credit figure/F1.

Third generation offspring – granddaughters and grandsons

Current perspective of diethylstilbestrol (DES) exposure in mothers and offspring


  • Diethylstilbestrol (DES) is a synthetic, non-steroidal estrogen of the stilbestrol group acting as an endocrine disruptor.
  • Adverse pregnancy outcomes, infertility, cancer, and early menopause have been identified in women exposed to DES, their offspring, and subsequent generations.
  • DES is one of the major disasters in medicine and it is mandatory to tackle and promote programs of DES-related cancer prevention.

2017 Review Abstracts

Diethylstilbestrol (DES) was an orally active estrogen prescribed to the pregnant women to prevent miscarriages. DES is known as a ‘biological time bomb’ and long-term effects of DES have been recorded in the mothers exposed to DES and their offspring (DES-daughters and DES-sons). Adverse pregnancy outcomes, infertility, cancer, and early menopause have been discovered in women exposed to DES, and some events occur in their offspring and subsequent generations. An increased risk of breast cancer is not limited to the DES-exposed daughters.

We were told that it “could take over 50 years” to detect the effects of DES exposure in future generations, due to the length of time required for diseases to manifest. It is predicted that cross-generational responses to the exposure of DES are possible due to epigenetic changes in the DNA.

The studies on the cohort of grandchildren (grandsons and granddaughters) whose mothers were exposed to DES prenatally (i.e., grandchildren had no direct DES exposure) are limited as they have just reached the age when relevant health problems could be studied.

It seems that the DES 3rd generation has also an increased risk for cancer. The epigenetic effects of DES could be manifested in this generation. DES could affect daughters of the exposed mothers as their oocytes might be developing at the critical stage, but transgenerational effect of DES, i.e., children of sons or daughters of DES mothers, may have an epigenetic basis.

In opposition to developmental epigenetics transgenerational epigenetics implies an absence of resetting of epigenetic states between generations. In fact,the exposure to endocrine disruptor chemical compounds is associated with abnormal DNA methylation and other epigenetic modifications, as well as altered expression of genes important for development and function of reproductive tissues as recently observed by Ho et al.

In a multi-center study, an increase of congenital disabilities in the sons and daughters of the 3rd generation was observed. Currently, there are no large human studies that show adverse events of DES for granddaughters. Kaufman et al. conducted a small cohort study on 28 DES granddaughters and found neither CCA nor abnormalities of the lower genital tract. On the other hand, granddaughters may have more menstrual problems and higher infertility rate compared to non-exposed granddaughters. Direct maternal DES exposure during pregnancy can cause not only an alteration to the reproductive capacity of the woman, but also this alteration may be passed on to next generation, a phenomenon that is called ‘DES granddaughter effect’ and DES granddaughters may also harbor a higher risk of ovarian cancer rather than breast cancer. In DES grandsons, the incidence of hypospadia is 20 times higher than unexposed grandsons, but the risk of developing such anomaly seems to be low.

There is an urgent need to find ways to stop the inheritance cycle of DES and prevent adverse effects of DES in the future generations. The present article reviews the health implications of DES exposure and screening exams currently recommended to DES daughters and their offspring.


  • Current perspective of diethylstilbestrol (DES) exposure in mothers
    and offspring
    , NCBI PubMed, 28461243, August 2017.
  • Image credit gstatic.

Diethylstilboestrol – A long-term legacy

Transgenerational effect of DES, i.e., children of sons or daughters of DES mothers, may have an epigenetic basis

2012 Study Abstract

Diethylstilboestrol (DES) is an endocrine disrupter which causes cancer in rodents.

It was prescribed in large amounts to treat women with gynaecological problems; some of the daughters of these women subsequently developed a rare cancer (vaginal clear cell adenocarcinoma) while genital abnormalities were found in some of the sons.

It was used for decades in livestock feed and this may have contaminated the food chain leading to the exposure of the more general population.

DES appears to cause epigenetic effects in animals and there is some evidence that this also occurs in man.

The mechanisms of carcinogenesis are complex and the effects are difficult to prove due to the background of dietary and environmental phyto- and xenooestrogens.

It has been suggested that, like other endocrine disrupters, DES may have acted as an obesogen in the human population.



Reproductive and hormone-related outcomes in DES third generation women

Reproductive and hormone-related outcomes in women whose mothers were exposed in utero to diethylstilbestrol (DES): A report from the US National Cancer Institute DES Third Generation Study

2019 Study Highlights

  • Studies of mice indicate intergenerational effects of DES exposure; i.e., effects in the offspring of prenatally DES-exposed animals.
  • We assessed DES exposure in relation to outcomes in a cohort of third generation women whose mothers were prenatally DES-exposed and unexposed.
  • Results suggested DES-exposed third generation women have increased risks of menstrual aberrations, preterm birth, and possibly ectopic pregnancy.
  • The data did not indicate an increase in same-sex orientation in DES-exposed third generation women.
  • Menstrual aberration and preterm birth in the DES-exposed third generation suggest intergenerational effects of endocrine disrupting chemicals in humans.


Animal studies suggest that prenatal exposure to diethylstilbestrol (DES) causes epigenetic alterations in primordial germ cells that affect the next generation, but human studies are sparse.

We assessed hormonally mediated outcomes in third generation women whose mothers were prenatally DES-exposed and unexposed.

Compared to the unexposed, DES-exposed third generation women had an increased risk of irregular menses and amenorrhea; the respective prevalence ratios and 95% confidence intervals (CI) in follow-up data were 1.32 (95% CI: 1.10, 1.60) and 1.26 (95% CI: 1.06, 1.49); associations were more apparent in third generation women whose prenatally DES-exposed mothers were affected by vaginal epithelial changes. The follow-up data also indicated an association with preterm delivery (relative risk (RR): 1.54; 95% CI: 1.35, 1.75).

DES third generation women may have an increased risk of irregular menstrual cycles, amenorrhea, and preterm delivery, consistent with inter-generational effects of endocrine disrupting chemical exposure in humans.


  • Reproductive and hormone-related outcomes in women whose mothers were exposed in utero to diethylstilbestrol (DES): A report from the US National Cancer Institute DES Third Generation Study, ScienceDirect, Reproductive Toxicology Volume 84, March 2019, Pages 32-38.
  • Featured image credit ars.els-cdn.