Hypothesis: Gastroschisis is a localised disruption of the abdominal layer. It occurs early in gestation, and the bowel is therefore bathing in the amniotic fluid and can be constricted at the level of the abdominal hole. The bowel is therefore submitted to different injuries partly attributable to the contact with amniotic fluid contaminated by digestive compounds and inducing an inflammatory reaction. Experimental studies on animal models and preliminary data in humans indicate that changing regularly the amniotic fluid (i.e. AMNIOECHANGE) would improve the outcome of theses fetuses and then neonates.