Key Findings from Recent Birth Defects and Pediatric Genetics Branch Projects

International Trends in Rates of Hypospadias and Cryptorchidism

A CDC scientist analyzed international trends in the rates of two birth defects that can affect males: hypospadias and cryptorchidism.

• Hypospadias is a birth defect characterized by the urethral opening not being correctly located at the tip of the penis. The urethral opening is usually located closer to the body on the ventral side of the penis in a boy with hypospadias. Surgery is often required.
    

• Cryptorchidism is when one or both of the testes have not descended into the scrotum by the time a full term infant is born. If it persists it can require surgery.
    

• Researchers from seven European nations and the United States have published reports of increasing rates of hypospadias during the 1960s, 1970s, and 1980s. Reports of increasing rates of cryptorchidism have come primarily from England. In the 1990s, these reports have become one focus of the debate over endocrine disruption.
    

• This study examines more recent data from a larger number of countries to determine whether such increases are worldwide and continuing and whether the increases show any geographic patterns.
    

• The International Clearinghouse of Birth Defects Monitoring Systems and individual systems provided the data. Countries were categorized into rough quintiles by gross domestic product in 1984.
    

• Hypospadias increases were most marked in two U.S. systems and in Scandinavia and in Japan. The increases leveled off in many systems after 1985. Increases were not seen in less affluent nations.
    

• Cryptorchidism rates were available for 10 systems. This anomaly clearly increased in two U.S. systems and in the South American system but not elsewhere. Since 1985, rates have declined in most systems.
    

• Better diagnosis, more complete reporting, and better surveillance systems may have contributed to or caused the upward trends in hypospadias. Possible real causes include demographic changes and endocrine disruption.

Results published in: Environmental Health Perspectives 1999;107:297-302. (Abstract)