Gastroschisis is an abdominal wall defect in the right paraumbilical region where bowel loops protrude outside the abdomen directly exposed to amniotic fluid without membrane coverage. Incidence is approximately 1/2000-4000 live births and has been increasing in recent years. Gastroschisis is more common in young mothers (<20 years). Unlike omphalocele: (1) defect is right paraumbilical (not midline), (2) protruding organs are not covered by membrane, (3) umbilical cord is in normal position (not at sac apex), (4) chromosomal anomaly association is low (10-15%). However, since bowel loops are directly exposed to amniotic fluid, bowel damage (thickened wall, matting, atresia) is specific to gastroschisis. Usually diagnosed on prenatal ultrasound in first or second trimester. Treatment is postnatal primary surgical closure or staged closure (silo).
Age Range
0-0
Peak Age
-
Gender
Equal
Prevalence
Rare
The embryological mechanism of gastroschisis is not fully elucidated but two main theories exist: (1) Right omphalomesenteric artery involution theory — when the right omphalomesenteric artery undergoes early involution, the right paraumbilical region of the abdominal wall it supplies suffers ischemic damage creating the defect; (2) Right umbilical vein involution theory — similar mechanism where early loss of the right umbilical vein leads to abdominal wall weakness. The defect is generally <4 cm in diameter, located between the right rectus muscle and umbilical ring. The umbilical cord is independent of the defect and at normal insertion — this is the most important distinguishing anatomical feature from omphalocele. Bowel loops are exposed to amniotic fluid without membrane — urea, meconium, and inflammatory mediators in amniotic fluid cause chemical damage to the bowel wall. This damage leads to serosal thickening (peel formation), bowel wall edema, matting (adhesion of bowel loops to each other), and bowel motility dysfunction. In advanced cases, bowel atresia, necrosis, or volvulus may develop.
The pathognomonic finding of gastroschisis: bowel loops floating freely in amniotic fluid without membrane coverage through a right paraumbilical defect. The umbilical cord is at normal insertion independent of the defect. The combination of these three findings (right paraumbilical defect + no membrane + normal cord position) confirms gastroschisis and distinguishes it from omphalocele (midline + membrane present + cord at sac apex).
Prenatal ultrasound reveals a defect in the right paraumbilical region of the fetal anterior abdominal wall. Bowel loops are seen floating freely in amniotic fluid without membrane coverage — this is the pathognomonic feature of gastroschisis. The umbilical cord is in normal position independent of the defect. The defect is generally small (<4 cm) and liver herniation is not expected. In early pregnancy (<14 weeks), bowel wall appears normal, while bowel wall thickening and matting develop with advancing gestational age.
Report Sentence
A defect is seen in the right paraumbilical region of the fetal anterior abdominal wall on prenatal US with bowel loops floating freely in amniotic fluid without membrane; umbilical cord in normal position; findings are consistent with gastroschisis.
With advancing gestational age, wall thickening, matting (adhesion between loops), and dilatation of extracorporeal bowel loops are seen. Bowel wall thickness is normally <3 mm but increases to >3-5 mm in gastroschisis. Matting is the inability to individually distinguish bowel loops, appearing as a dense mass. Intra-abdominal bowel dilatation is a sign of obstruction. The severity of these findings affects delivery timing — significant bowel damage suggests earlier delivery.
Report Sentence
Bowel wall thickening (>3 mm) and matting are seen in extracorporeal bowel loops; these findings indicate amniotic fluid damage and close follow-up for delivery timing is recommended.
Dilatation of intra-abdominal bowel loops (lumen diameter >7 mm) is a sign of bowel obstruction. Obstruction generally occurs from compression of bowel loops at the passage point through the defect or development of atresia. Intra-abdominal bowel dilatation indicates worse prognosis and need for more aggressive surgical approach. Polyhydramnios may accompany — proximal obstruction impairs amniotic fluid absorption.
Report Sentence
Dilated intra-abdominal bowel loops (lumen diameter >7 mm) are seen suggesting bowel obstruction; coordination with pediatric surgery for delivery timing and surgical planning is recommended.
On fetal MRI T2-weighted images, bowel loops protruding through the right paraumbilical defect are seen freely in amniotic fluid. Bowel lumen is T2 hyperintense (intraluminal fluid), bowel wall shows intermediate signal. Absence of membrane is also confirmed on MRI — organs are directly surrounded by amniotic fluid. Bowel wall thickening and matting are better evaluated on T2. Fetal MRI is superior for calculating abdominal cavity volume and screening for additional anomalies.
Report Sentence
On fetal MRI, bowel loops protruding through the right paraumbilical defect are seen without membrane in amniotic fluid; consistent with gastroschisis.
Doppler ultrasound evaluates mesenteric vascular flow. Superior mesenteric artery (SMA) flow pattern reflects bowel perfusion. Abnormal SMA Doppler (increased resistance index >0.8) suggests bowel ischemia. Increased resistance or absent/reversed diastole on umbilical artery Doppler is a sign of fetal distress. These findings are important parameters affecting delivery timing.
Report Sentence
SMA flow pattern has been evaluated on Doppler examination; normal flow pattern is observed on umbilical artery Doppler.
Criteria
Isolated abdominal wall defect, no bowel atresia/necrosis/volvulus, 85-90% of cases
Distinct Features
Primary surgical closure usually possible, survival >95%, bowel function recovers within weeks
Criteria
Accompanied by bowel atresia, necrosis, volvulus, perforation, or closing gastroschisis (narrowing defect)
Distinct Features
Multiple surgeries may be needed, prolonged parenteral nutrition, short bowel syndrome risk, mortality 10-20%
Criteria
Defect narrows in utero compressing bowel loops → bowel ischemia/necrosis
Distinct Features
Requires emergent cesarean, bowel dilatation + defect narrowing + abnormal Doppler on US, worst prognosis
Distinguishing Feature
Omphalocele is midline defect, membrane-covered, cord at sac apex; gastroschisis is right paraumbilical, no membrane, cord in normal position; chromosomal anomaly risk much higher in omphalocele (50-70% vs 10-15%)
Distinguishing Feature
Ruptured omphalocele may make differentiation from gastroschisis difficult; in ruptured omphalocele, cord still attaches to sac remnant and liver is usually also herniated; differentiation made in clinical context
Distinguishing Feature
Body stalk anomaly is a lethal condition including severe abdominal wall defect + short umbilical cord + scoliosis + extremity anomalies; unlike gastroschisis, multiple major anomalies accompany and prognosis is very poor
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
specialist-referralGastroschisis requires multidisciplinary planning after prenatal diagnosis. Prenatal follow-up: US every 2-3 weeks to evaluate bowel status (wall thickness, matting, dilatation), amniotic fluid volume, and fetal growth. Delivery: generally planned delivery at 37 weeks is recommended — earlier if significant bowel damage. Cesarean vs vaginal delivery is debated but cesarean is preferred in complex cases. Postnatal treatment: primary surgical closure in simple gastroschisis; staged closure (preformed silo → gradual reduction → closure) for large defects or significant bowel damage. Prognosis: simple gastroschisis survival >95%; complex gastroschisis mortality 10-20% with short bowel syndrome risk.
Gastroschisis requires emergency surgical intervention after birth. Primary closure or staged silo technique is performed. Feeding difficulties and prolonged hospitalization are expected due to bowel wall damage (chemical peritonitis). Bowel atresia (10-15%) and volvulus complications may occur. Long-term prognosis is generally good (>90% survival).