What are hypospadias and epispadias?

Hypospadias and epispadias are birth differences that result from atypical development of the penis during embryological development. Normally the urethra (the tube that serves as a conduit through the penis for passage of urine and semen) runs the entire length of the penis, forming an opening at the tip. However, the penis sometimes does not form correctly and the urethra fails to reach the tip of the penis. The incompletely-developed urethra may form an opening at the under side of the penis (hypospadias) or the upper side of the penis (epispadias).

How common are hypospadias and epispadias?

Hypospadias is one of the most common birth differences, occurring to some degree in as many as 1 out of every 125 boys (according to the Centers for Disease Control and Prevention). Epispadias, which is often more severe than hypospadias, occurs much less frequently and can occur in girls (although epispadias in girls is very rare).

How do I know whether the condition is mild or severe?

Severity of hypospadias or epispadias can vary significantly from one person to another. In the mildest cases, the urethral opening forms just short of the tip of the penis. In more severe cases, the opening forms closer to the scrotum. Hypospadias and epispadias are also often associated with severe curvature of the penis, or chordee, especially in more severe cases. Epispadias may also be associated with a severe condition known as bladder exstrophy, in which the bladder forms outside of the abdominal cavity.

What problems do hypospadias and epispadias cause?

Consequences depend in large part on the severity of the condition. The most common consequences are difficulty urinating while standing and an atypical appearance of the penis that differs from other boys. If chordee is present, the severe curvature of the penis might also cause painful erections. Many boys with these conditions are more susceptible to urinary tract infections because of the shortened urethra.

Will boys with hypospadias/epispadias be able to father children when they grow up?

There is no evidence that men with these conditions have more infertility problems than anyone else. However, in severe cases the urethral opening may be so far from the tip of the penis that semen may not easily enter the vagina. Even in those instances, insemination will likely be possible without medical intervention. Women with epispadias may have more difficult pregnancies than other women.

What causes hypospadias/epispadias?

Until 8 to 10 weeks of development, embryos have neither male nor female sex organs and genitalia, but instead have a genital tubercle, genital folds and genital swellings. The “default” developmental pathway is female development, with genital folds becoming labia minora, the tubercle forming the clitoris, and the genital swellings forming the labia majora. However, male hormones (testosterone and dihydrotestosterone, or DHT) secreted by the male embryo beginning around 10 weeks of development alter the default developmental pathway. The male hormones cause the genital swelling to create the scrotum, the genital folds to fuse together to become the shaft of the penis, and the genital tubercle to form the glans or tip of the penis. Normally in male development the genital folds fuse completely so that the penis completely surrounds the urethra all the way to the tip. Hypospadias/epispadias results when the genital folds fail to fuse properly, leaving part of the penis open and the urethra incompletely developed. No clear underlying cause of the incomplete fusion has been identified, and there are likely many contributing factors which act together to cause the condition. Studies indicate that genes play a role; however, men with hypospadias or epispadias will not necessarily father children with the condition. Environmental pollutants that resemble female hormones (estrogens) or interfere with male hormones may also play a role, but the studies were performed in animals and may not be relevant to humans. Some medications may also contribute. For example, pregnant women are advised not to come in contact with the baldness medication Propecia, which blocks formation of DHT, because it may increase the incidence of hypospadias.