Bladder exstrophy is the most common in the larger group of birth defects called the bladder exstrophy-epispadias complex (BEEC). Children with BEEC have one of the following: BEEC 
Epispadias. This is the least severe form of BEEC, in which the tube to expel urine (urethra) doesn't fully develop.

Bladder exstrophy. This defect causes the bladder to form on the outside of the body. The bladder is also turned inside out. Usually, bladder exstrophy will involve organs of the urinary tract, as well as the digestive and reproductive systems. Defects of the abdominal wall, bladder, genitals, pelvic bones, final section of the large intestine (rectum) and opening at the end of the rectum (anus) can occur.
Children with bladder exstrophy also have vesicoureteral reflux. This condition causes urine to flow the wrong way — from the bladder back up into the tubes that connect to the kidneys (ureters). Children with bladder exstrophy also have epispadias.


Cloacal exstrophy. Cloacal exstrophy (kloe-A-kul EK-stroh-fee) is the most serious form of BEEC. In this condition, the rectum, bladder and genitals don't fully separate as the fetus develops. These organs may not be correctly formed, and the pelvic bones are affected as well.
The kidneys, backbone and spinal cord also may be affected. Most children with cloacal exstrophy have spinal abnormalities, including spina bifida. Children born with protruding abdominal organs probably also have cloacal exstrophy or bladder exstrophy.

