Hypospadias in sons of women exposed to DES in utero

These 2005 findings confirm an increased risk of hypospadias in the sons of women exposed in utero to DES and the transgenerational effect of DES


Transgenerational effects of diethylstilbestrol (DES) have been reported in animals and humans. Alerted by two case reports, Klip H et al conducted a cohort study of all sons of a Dutch cohort of 16 284 women with a diagnosis of fertility problems and obtained a 67% response rate; their findings suggest an increased risk of hypospadias in the sons of women exposed in utero to DES. The mothers of 205 boys reported DES exposure in utero, and four of these boys were reported to have hypospadias. This defect was reported in only 8 of the remaining 8729 sons (prevalence ratio 21.3 (95% confidence interval (CI) 6.5–70.1)).

In a retrospective study, we analysed 32 406 computerized obstetrical and pediatric files at Port-Royal Maternity Center, covering births from 1 January 1993 to 31 December 2002. We compared the prevalence rate of hypospadias among 17 633 boys of mothers with and without in utero DES exposure.

The mothers of 240 boys had reported DES exposure in utero. Three (1.23%) were reported to have hypospadias. Obstetric records of the remaining 17 393 children reported hypospadias for only 44(0.5%◦) (prevalence ratio 4.99 (95% CI 1.2–16.8, p = 0.02)). All cases of hypospadias were medically confirmed by the pediatric files.

Our findings confirm an increased risk of hypospadias in the sons of women exposed in utero to DES and the transgenerational effect of DES.

The lower prevalence ratio in our study (4.99) than in the Dutch cohort (21.3) is probably due to the difference in the underlying populations: the Dutch cohort was selected for the criteria of infertility and is thus necessarily different from our general population.

Klip’s data came from questionnaires addressed to women who had consulted for infertility and been previously enrolled in a cohort. The analysis was based on a 67% response rate. We note that the 95% CI of the relative risk (RR) in the Klip study (6.5–70.1) is compatible with the RR in the present study. On the basis of both the studies, the true RR may range between 6.5 (lower range of Dutch study) and 16.8 (upper range of our study) and, given the possible bias of the Dutch study, the true RR may well be lower than 16.8.

Our study examined a large continuous series of woman who gave birth at Port Royal. During the study period, women were systematically asked about their own in utero exposure to DES. All of the obstetrical and pediatric records of our population were analysed.

The prevalence of hypospadias in our control series was 2.5 per 1000, which corresponds to the prevalence in the general French population −2.89 per 1000 male newborns. The prevalence in the control series for Klip’s population was only 0.9 per 1000.

The importance of understanding the mechanism of hypospadias warrants additional studies. Van Tongeren et al. point out that, especially in urban areas, mothers’ occupations (such as hairdressing and working in beauty salons) can increase exposure to potential endocrinedisrupting chemicals Van Tongeren et al (2002). Our study does not enable us to determine whether the mothers of sons with hypospadias were exposed to higher levels of or at higher rates to such chemicals.


  • Hypospadias in sons of women exposed to diethylstilbestrol in utero, NCBI PubMed PMID: 15906411, 2005 May.
  • Featured image credit Piron Guillaume.

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