The natural history of gastroschisis during fetal life: development of the fibrous coating on the bowel loops.

Patients with gastroschisis have a paraumbilical defect of the anterior abdominal wall through which bowel loops protrude. These bowel loops are edematous and covered by a fibrous coating. The moment of occurrence of gastroschisis as well as the development of the fibrous coating are unknown. This prompted an investigation of 26 human embryos and fetuses with gastroschisis at various developmental stages (crown-rump length 25-240 mm) and two stillborn fetuses (gestational age 30 weeks) with gastroschisis, as well as resected material from ten newborns (gestational age 33-40 weeks) operated for gastroschisis. Progressive changes of the serosa were only noted after the 30th week of gestation and consisted of an amniotic fluid peritonitis and progressive fibrosis. The changes are in agreement with experimental data and correlate with changes in the composition of amniotic fluid. The findings prove that gastroschisis is a very early occurrence, while the fibrous coating is a late development.