OC16.08: Fetal gastroschisis: exploring stenotic effects at umbilical ring beyond bowel involvement

Fetuses with gastroschisis (GS) exhibit a high incidence of Fetal growth restriction (FGR) while the reason remains elusive. This retrospective study aims to investigate the stenotic effects--umbilical vein (UV) compression within the hernial orifice and its correlation with placental fetal vascular malperfusion (FVM) and FGR. A single-centre retrospective review of MRI scans obtained in fetuses with gastroschisis was performed. Co-occurrence network analysis(NA) was utilised to discover phenotypic feature interconnections. Morphological measurements including abdominal wall defect size, maximum small intestine diameter, UV diameter, and placenta characteristics were subjected to PCA (Principal Component Analysis) for multivariate data classification between complex and simple GS, as well as between FGR and non-FGR phenotypes. Furthermore, 1:1 age-matched omphalocele cases were incorporated for comparison on the UV diameter, FVM, and T2* signal intensity (SI) differences between the left and right lobes of the liver. Totally 86 cases postnatally confirmed as GS were included, and 30/86 cases were classified as complex GS - presenting intestinal obstruction, volvulus, or perforation. NA displays robust connections between FGR and placenta FVM, umbilical vein stenosis at the defect, and intra-abdominal UV post-stenotic dilatation. FGR was observed in 66% of GS, and even higher in complex GS (85%). Placentas in the GS + FGR group were significantly thickened, accompanied by more frequent lobules and hemorrhages, associated with UV stenosis at the defect. And significant T2* SI differences between the left and right lobe of the liver were observed. PCA results showed different clustering patterns between gastroschisis-FGR, gastroschisis +FGR, and omphalocele groups. Our study demonstrates intricate connections between GS, FGR, UV stenosis at the defect, and placental FVM, revealing the hemodynamic heterogeneity associated with FGR. Severe UV compression might be used to identify high-risk candidates for prenatal surgery.