Supplementary Material for: Diagnostic Accuracy of Prenatal Ultrasound in Identifying Jejunal and Ileal Atresia

Introduction: Small bowel atresia (SBA) is one of the most common causes of congenital intestinal obstruction. However, the accuracy of prenatal ultrasound in diagnosing this condition has not been entirely ascertained. The aim of this study was to analyse the predictive accuracy of ultrasound in detecting SBA prenatally. Methodology: Retrospective study of all cases with prenatal suspicion or postnatal confirmed SBA seen in a tertiary fetal medicine and pediatric surgery units from 2007 to 2013. Cases with duodenal atresia were excluded from the study. The predictive accuracy of ultrasound and different ultrasound signs, alone and in combination, was calculated. Results: 65 fetuses with prenatal suspicion or postnatal confirmed SBA were enrolled. 58 cases had full data and were included in the analysis. Predictive accuracy of ultrasound in detecting the presence of SBA was poor, with a sensitivity of 50% (95% CI 26.0-74.0) and a specificity of 70.59% (95% CI 52.5-84.9). The presence of both bowel dilatation ≥17 mm and polyhydramnios after 32 weeks of gestation slightly increased sensitivity (66.67%, 95% CI 34.9-90.1) and specificity (80.00%, 95% CI 44.4-97.5). Conclusions: In case of suspicion of SBA before the 3rd trimester, an ultrasound after 32 weeks should be performed to confirm the presence of both polyhydramnios and bowel dilatation >17 mm.