Parental subfertility and hypospadias and cryptorchidism in boys: results from two Danish birth cohorts

Compared to those conceived spontaneously, boys conceived after fertility treatment had higher occurrence of hypospadias, but not cryptorchidism. Waiting time-to-pregnancy was not associated with hypospadias or cryptorchidism.

Volume 110, Issue 5, Pages 826–832


Linn Håkonsen Arendt, Ph.D., Morten Søndergaard Lindhard, Ph.D., Camilla Kjersgaard, M.D., Tine Brink Henriksen, Ph.D., Jørn Olsen, Ph.D., Cecilia Høst Ramlau-Hansen, Ph.D.



To study if parental subfertility is related to the occurrence of the male genital anomalies, cryptorchidism and hypospadias.


Population-based cohort study.


Not applicable.


A total of 80,220 singleton boys and their mothers from the Danish National Birth Cohort and the Aarhus Birth Cohort.



Main Outcome Measure(s)

The two congenital anomalies; cryptorchidism and hypospadias, registered within the Danish National Patient Register up until December 31, 2012.


By means of Cox regression analyses, we found no associations between waiting time-to-pregnancy (TTP) and cryptorchidism or hypospadias among those who conceived spontaneously. The highest hazard ratio for cryptorchidism was seen among boys of couples with a TTP>12 months who conceived after fertility treatment (adjusted hazard ratio [aHR] 1.19, 95% confidence interval 0.92–1.55). For hypospadias, we found that boys of couples with a TTP>12 months who conceived after fertility treatment, had a 71% higher risk of hypospadias (aHR 1.71, [95% confidence interval 1.24–3.36]) as compared with boys of couples with a TTP<5 months.


The findings from this study showed that boys of couples with TTP>12 months who conceived after fertility treatment, had a higher occurrence of hypospadias than boys conceived spontaneously of couples with a short TTP. Among those who conceived spontaneously, TTP was not associated with hypospadias or cryptorchidism. These findings indicate that fertility treatment or severity of subfertility is related to hypospadias.



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Go to the profile of Mary Samplaski
over 4 years ago

This is interesting data, and I will be curious to see how it evolves. Were the authors able to tease out if this incidence was different after frozen embryo transfer, when the uterus has had time to "reset"?