The two main abdominal wall defects are omphalocele and gastroschisis.
Omphalocele
An omphalocele is caused by an opening (defect) in the middle of the abdominal wall at the bellybutton (umbilicus). The skin, muscle, and fibrous tissue are missing. The intestines spill (herniate) out through the opening and are covered by a thin sac. The umbilical cord is in the center of the defect.
An omphalocele commonly occurs along with other birth defects (such as heart defects Overview of Heart Defects About one in 100 babies is born with a heart defect. Some are severe, but many are not. Defects may involve abnormal formation of the heart's walls or valves or of the blood vessels that enter... read more and kidney defects Kidney Defects There are several different birth defects that affect the kidneys (the two organs that filter waste from the blood to make urine). These defects are not usually apparent at the doctor's examination... read more ) and with specific genetic syndromes (such as Down syndrome Down Syndrome (Trisomy 21) Down syndrome is a chromosome disorder caused by an extra chromosome 21 that results in intellectual disability and physical abnormalities. Down syndrome is caused by an extra chromosome 21... read more 
, trisomy 18 Trisomy 18 Trisomy 18 is a chromosomal disorder caused by an extra chromosome 18 that results in intellectual disability and physical abnormalities. Trisomy 18 caused by an extra chromosome 18. Infants... read more 
, trisomy 13 Trisomy 13 Trisomy 13 is a chromosomal disorder caused by an extra chromosome 13 that results in severe intellectual disability and physical abnormalities. Trisomy 13 is caused by an extra chromosome 13... read more 
, and Beckwith-Wiedemann syndrome).
Gastroschisis
Gastroschisis also is an abnormal opening of the abdominal wall. In gastroschisis, the opening is near the bellybutton (usually to the right) but not directly over it, like in omphalocele. Like in omphalocele, the opening allows the intestines to spill out but unlike omphalocele, the intestines are not covered by a thin sac.
Before birth, because the intestines are not covered by a sac, they may be damaged by exposure to amniotic fluid, which causes inflammation. The inflammation irritates the intestine, which can result in complications such as problems with movements of the digestive system, scar tissue, and intestinal obstruction Intestinal Obstruction An obstruction of the intestine is a blockage that completely stops or seriously impairs the passage of food, fluid, digestive secretions, and gas through the intestines. The most common causes... read more .
(See also Overview of Digestive Tract Birth Defects Overview of Digestive Tract Birth Defects A birth defect can occur anywhere along the digestive tract—in the esophagus, stomach, small intestine, large intestine, rectum, or anus. The digestive organs may be incompletely developed or... read more .)
Diagnosis of Abdominal Wall Defects
Blood tests
Usually prenatal ultrasonography
Doctors may suspect gastroschisis if the level of alpha-fetoprotein Second-Trimester Screening Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more (a protein produced by the fetus) in the mother's blood is abnormally high during pregnancy.
Both omphalocele and gastroschisis are usually diagnosed before birth with routine prenatal ultrasonography Ultrasonography Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more . If not, the defects are very obvious as soon as the infant is delivered.
Treatment of Abdominal Wall Defects
Surgery
Once the infant is delivered, the exposed intestines are covered with a sterile dressing to keep them moist and protected and the infant is given fluids and antibiotics by vein. A long, thin tube is passed through the nose and placed in the stomach or intestine (nasogastric tube) to drain digestive fluid that collects in the stomach.
Surgery is required to replace the intestines in the abdomen and close the opening. If possible, surgery to repair the defect is done soon after birth. However, the skin of the abdominal wall often must be stretched for a few days before surgery so there is enough tissue to cover the opening. If the defect is large, doctors may need to create skin flaps to close it. If a large amount of intestine is sticking out, it is wrapped in a protective covering (called a silo) and gradually moved back into the abdomen over several days or weeks. When all the intestines are back in the abdomen, the opening is surgically closed.
