Bladder exstrophy is a congenital anomaly that exists along the spectrum of the exstrophy-epispadias complex, and most notably involves protrusion of the urinary bladder through a defect in the abdominal wall. Its presentation is variable, often including abnormalities of the bony pelvis, pelvic floor, and genitalia. The underlying embryologic mechanism leading to bladder exstrophy is unknown, though it is thought to be in part due to failed reinforcement of the cloacal membrane by underlying mesoderm. Exstrophy means the inversion of a hollow organ. Signs and symptoms The classic manifestation of bladder exstrophy presents with: A defect in the abdominal wall occupied by both the exstrophied bladder as well as a portion of the urethra A flattened puborectal sling Separation of the pubic symphysis Shortening of a pubic rami External rotation of the pelvis. Females frequently have a displaced and narrowed vaginal orifice, a bifid clitoris, and divergent labia. Cause The cause is not yet clinically established but is thought to be in part due to failed reinforcement of the cloacal membrane by underlying mesoderm. Diagnosis In a small retrospective study of 25 pregnancies five factors were found to be strongly associated with a prenatal diagnosis of bladder exstrophy: Inability to visualize the bladder on ultrasound A lower abdominal bulge A small penis with anteriorly displaced scrotum A low set umbilical insertion Abnormal widening of the iliac crests While a diagnosis of bladder exstrophy was made retrospectively in a majority of pregnancies, in only three cases was a prenatal diagnosis made. Management The extreme rarity of the disease limits the surgical opportunities to practice the complex closure required in these patients. For this reason, patients have the best outcomes when the bladder closures are performed at high volume centers where surgical and nursing teams have extensive experience in caring for the disease. The highest volume center in the United States, and the world, is the Johns Hopkins Hospital in Baltimore, Maryland; they have seen over 1300 exstrophy patients in the past 50 years. Upon delivery, the exposed bladder is irrigated and a non-adherent film is placed to prevent as much contact with the external environment as possible. In the event the child was not born at a medical center with an appropriate exstrophy support team then transfer will likely follow. Upon transfer, or for those infants born at a medical center able to care for bladder exstrophy, imaging may take place