Gastroschisis

Gastroschisis is a type of abdominal wall defect in which the intestines and sometimes other organs develop outside the fetal abdomen through an opening in the abdominal wall. This defect is the result of obstruction of the omphalomesenteric vessels during development. It is often detected through AFP screening or a detailed fetal ultrasound. Gastroschisis is also called paraomphalocele, laparoschisis, or abdominoschisis.

Omphalocele is a similar birth defect, but it involves the umbilical cord, and the organs are enclosed in a membranous sac instead of directly in the amniotic fluid.

Genetic counseling and further genetic testing, such as amniocentesis, may be offered during the pregnancy, as some abdominal wall defects are associated with genetic disorders. If there are no additional genetic problems or birth defects, surgery soon after birth can often repair the opening.

Embryology
During the fourth week of development, the lateral body folds move ventrally and fuse in the midline to form the anterior body wall. Incomplete fusion results in a defect that allows abdominal viscera to protrude through the abdominal wall. The bowel typically herniates through the rectus muscle, lying to the right of the umbilicus.

Mortality and Morbidity
Current advances in surgical techniques and intensive care management for neonates have increased the survival rate to 90%, in adequate settings. The possibility of prenatal diagnosis either through echosonogram or any other method available allows the mother to be referred to an adequate center where a caesarean section can be made at term (or as close to full term as possible) and allow the immediate surgery to be performed in the newborn. The morbidity is closely related to the presence of other malformations and complications of the wound or the intestine. Patients frequently require more than one surgery.

Statistics
The malformation is slightly more frequent in males than females. The frequency of gastroschisis is associated with young maternal age, and low number of gestations.

Causes and Risk Factors
High risk pregnancies such as the ones complicated with infections, teen aged mothers, smoking, drug abuse, or anything that contributes to low birth weight can increase the incidence of gastroschisis, which is more frequent in small for gestational age newborn. Either if the intrauterine growth retardation can facilitate the apparition of gastroschisis or if the abdominal wall defect impairs fetal growth is not clear yet.