OP12.09: Ultrasound markers predicting complex gastroschisis and adverse outcome: a longitudinal prospective nationwide cohort study

OBJECTIVES: To identify antenatal ultrasound markers and their predictive value in differentiating between simple and complex gastroschisis. METHODS: Prospective nationwide study in which serial longitudinal ultrasound examinations were performed at regular specified intervals between 20 and 37 weeks in isolated fetal gastroschisis cases. The primary outcome was simple or complex (bowel atresia, volvulus, perforation or necrosis) gastroschisis at birth. Fetal biometry, the occurrence of polyhydramnios, intra- and extra-abdominal bowel diameters and the pulsatility index (PI) of the superior mesenteric artery were assessed. Linear mixed modelling was used to compare the individual trajectories of both simple and complex cases. Logistic regression analysis was used to estimate the strength of association between the ultrasound parameters and outcome. RESULTS: 104 cases of isolated fetal gastroschisis were included. Four intra uterine deaths occurred. Eighty-one (81%) liveborn infants had simple and 19 (19%) had complex gastroschisis. We found no relationship between fetal biometric variables and complex gastroschisis. The PI of the superior mesenteric artery was significantly lower than in healthy controls, but did not differentiate between simple and complex cases. Both intra- and extra-abdominal bowel diameters were larger in complex cases (P<0.001 and P<0.05, respectively). If ≥ 3 measurements of the intra-abdominal bowel diameter were at or above the P97.7 in not necessarily successive measurements for a particular fetus, it was at increased risk of having complex gastroschisis (relative risk 1.56; 95% CI 1.02 - 2.10; positive predictive value 50.0 %, negative predictive value 81.4 %). CONCLUSIONS: Based on this large prospective longitudinal study we found that intra-abdominal bowel dilation when repeatedly present during fetal development is the only variable to differentiate between simple and complex gastroschisis. However its positive predictive value and therefore the clinical usefulness is limited. This article is protected by copyright. All rights reserved.