Hypospadias: A birth defect of the penis involving the urethra (the transport tube leading from the bladder to discharge urine outside the body). The urethra normally travels in the male through the full length of the penis so that the stream of urine comes from the urethral opening at the tip of the penis. However, in hypospadias the urethra does not go all the way through the penis but, instead, opens on the underside of the shaft of the penis or below the penis.
Hypospadias is relatively common, affecting approximately 1 in every 500 newborn boys. Hypospadias can occur as an isolated birth defect in an otherwise normal child or it can be part of a multiple malformation syndrome. There is no association between the mother's use of loratadine (Claritin) in early pregnancy and the occurrence of hypospadias in her son.
In mild type (first-degree) hypospadias, the urethral opening is below the tip but still nearby (on what is called the glans). In moderate (second-degree) hypospadias, the urethra opens closer to the body on the underside of the shaft of the penis. In severe (third-degree) hypospadias, the urethal opening is below the penis on the skin and this is called a perineal hypospadias.
In a child with hypospadias, the urine comes from an opening that is on the underside of the penis or below the penis. With moderate-to-severe degrees of hypospadias, the boy will therefore usually sit to urinate. Some cases of first-degree hypospadias are so mild as to not require treatment.
If the hypospadias needs to be repaired, this is done by surgery. The aim is to repair and reconstruct the urethra. Depending on the degree of the hypospadias, the surgery can range from relatively simple to very challenging.
The opposite of hypospadias is epispadias, a less common birth defect in which the urethra opens prematurely on the upperside of the penis or above it.