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Gastroschisis

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diagram of
gastroschisis
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What is gastroschisis?

Gastroschisis refers to a small opening or "hole" in the abdominal wall which is usually located to the right of the umbilical cord insertion. It occurs as a result of incomplete closure of the skin folds around the 6th week of development. Usually only the stomach and intestines are herniated, while the liver is never herniated. Gastroschisis is differentiated from other abdominal wall defects by the absence of a membranous covering over the exposed abdominal contents.

It is more commonly seen with young mothers. It is not associated with chromosomal abnormalities or other organ problems. However, approximately 10% to 15% of babies have some additional intestinal abnormality such as intestinal atresia. Gastroschisis occurs in approximately 1 in 3,600 births and the incidence has increased significantly over the last 25 years.

What testing is recommended during the pregnancy?

Gastroschisis is diagnosed by prenatal ultrasound in the vast majority of cases. A screening prenatal blood test known as maternal serum alpha-fetoprotein (MSAFP) is a sensitive marker for abdominal wall defects.

Serial ultrasounds are scheduled to monitor the baby's growth and allow for careful examination of the exposed bowel. The bowel may become thickened and dilated the longer it remains exposed to amniotic fluid and become constricted at the abdominal wall opening. Known complications that may occur during the third trimester include decreased fetal growth, reduced amniotic fluid levels, preterm labor and in utero fetal demise. Therefore, increased fetal surveillance during the third trimester with NST and serial ultrasounds is advised.

Are there special considerations planned for the delivery?

It is recommended that the delivery of the baby is planned at a hospital that is prepared for high-risk deliveries with a neonatal intensive care and pediatric surgical services. This will help facilitate coordination between obstetrical, neonatal and pediatric surgical teams.

Several studies have been preformed to compare vaginal delivery to Cesarean section for gastroschisis. There is no convincing evidence to support better outcomes with Cesarean delivery. We recommend vaginal delivery unless there is a specific obstetrical indication for a C-section delivery. In rare cases, early delivery may be recommended if there is prenatal evidence of threatened bowel.

Is there fetal treatment for gastroschisis?

Serial amnio-exchange (removing amniotic fluid with a needle and replacing with saline solution) has been proposed to limit bowel damage in gastroschisis. This strategy does not address the problem of intestinal constriction at the level of the abdominal wall, and no compelling evidence supports this therapy at this time.

What is the treatment for gastroschisis?

If the defect is small and there is sufficient abdominal domain (space inside the abdomen), it may be possible to reduce the intestines and close the defect immediately after birth. If there is not sufficient abdominal domain to reduce the intestines, a pre-formed silastic silo is placed at the bedside immediately after birth to protect the intestines and limit fluid losses. The intestines are gradually reduced into the abdominal cavity over several days to a week. Once the contents are reduced, the baby is taken to the operating room for formal closure of the defect. If an intestinal atresia (disconnected intestine) is found at birth, the intestines are still usually placed back into the abdominal cavity because they are too inflamed to sew together. They are re-connected at approximately 4 to 6 weeks of age when the inflammation has subsided. The baby will usually require mechanical ventilation and receive pain medication during the period of surgical treatment.

Are there health problems that are more common among babies with gastroschisis?

Although the majority of babies with gastroschisis do well in the long term, many have feeding difficulties in the neonatal period. Initially, all babies with gastroschisis receive intravenous nutrition. Depending on the degree of intestinal damage, it may take several weeks until a baby is able to tolerate an elemental (pre-digested) formula. Feedings are started slowly as a continuous drip through a feeding tube, then gradually transitioned to oral bolus feeds. A small percentage of babies with gastroschisis will have hypoperistalsis syndrome (slow movement through the intestine) and will need intravenous nutrition for a prolonged period of time which may lead to liver injury. In addition, occasional gastroschisis babies will suffer a loss of intestine secondary to volvulus (twisting) of premature closure at the abdominal wall defect in utero. These infants are at high-risk for short-gut syndrome and TPN (intravenous nutrition) dependence.

Can this happen again with another pregnancy?

The risk of gastroschisis occurring in another pregnancy is approximately 4%. It is referred to as a sporadic event with a multi-factorial cause, though there have been a few reported familial cases. Maternal serum AFP testing and prenatal ultrasound should be offered in future pregnancies. Your doctor and a genetic counselor will review the risk in your family.