The causes of epispadias are not known. It may occur because the pubic bone does not develop properly.
Epispadias can occur with bladder exstrophy. In this rare birth defect, the bladder is inside out and sticks through the abdomen wall. Epispadias can also occur with other birth defects.
Epispadias occurs in 1 out of every 117,000 newborn boys and 1 in 484,000 newborn girls. The condition is usually diagnosed at birth or soon afterward.