When does bladder exstrophy develop?
The condition of exstrophy occurs during the development of the embryo (the name given to the baby during this stage) very early in the pregnancy, about 4 to 5 weeks after conception. The cause and nature of the faulty development is not exactly certain. It is 4 to 5 weeks after conception that the various organs and different types of muscles and tissues of the body begin to form from layers of cells that separate, divide and fold. One theory suggests that something goes wrong during this early folding and separation, causing the cloacal membrane to fail to close, leaving the bladder outside of the abdominal wall. A second theory proposes that the layer of skin which forms over the bladder at this stage is thin and unable to hold in the bladder. It pulls apart, again leaving the bladder inside out.