Endocrine Abstracts

The prevalence of congenital malformations such as hypospadias and cryptorchidism in boys has increased over the past decades, following time trends and geographic distribution of adult reproductive disorders such as testicular cancer and impaired semen quality. This suggests a common prenatal origin of a testicular dysgenesis syndrome. During the first postnatal months, the pituitary–gonadal axis is activated, which can be used as a diagnostic window of testicular function close to suspected adverse effects in utero.

In our prospective, population-based cohort of 2562 newborn boys from Denmark and Finland, we found a higher prevalence of cryptorchidism and hypospadias in Danish than Finnish boys. Healthy Danish boys had smaller testes and showed less testicular growth during infancy, and their level of serum inhibin B was lower. In addition to low birth weight, being small for gestational age and prematurity, regular moderate maternal alcohol consumption and mild diabetes was found to be a risk factor for cryptorchidism. Environmental chemicals were measured in breast milk samples from mothers of cryptorchid and healthy boys. Positive associations were found between cryptorchidism and polybrominated diphenyl ethers (flame retardants) and polychlorinated pesticides. The content of phthalate monoesters (plastic emollients) was negatively correlated with serum testosterone levels.

Our findings suggest, that perinatal exposure to some environmental chemicals may have adverse effects on testicular development in humans. This is of concern, as the foetus and infant will be persistently and simultaneously exposed to many chemicals.