Prenatal Ultrasound in Predicting the Need for Postnatal Surgery in Fetal Non‐duodenal Small Bowel Dilation

The accuracy of prenatal ultrasound in recognizing fetal non‐duodenal small bowel dilation (ND‐SBD) due to obstructive conditions requiring neonatal surgery is not well established. We assessed the positive predictive value (PPV) of prenatal 2‐dimensional (2D) ultrasound measurement of the small bowel diameter for identifying fetuses with ND‐SBD who will require postnatal surgical intervention. We systematically searched PubMed, Embase, Web of Science, Scopus, and Cochrane with terms related to fetal bowel dilation and postnatal outcome. For each included study, we estimated the PPV of prenatal ultrasound in predicting the need for neonatal surgery among live‐born, evaluable newborns classified as having a prenatal diagnosis of ND‐SBD, and performed a Bayesian random‐effects meta‐analysis of proportions to estimate the pooled PPV across studies. We identified 10 manuscripts, comprising 390 fetuses with a prenatal diagnosis of ND‐SBD, of which 341 from 9 studies had data available for analysis. The observed PPV for postnatal surgery ranged from 8 to 82%, with a pooled estimate of 56% (90% credible interval (CrI) [44%, 67%]). Heterogeneity between studies was elevated, with an I ² of 84.8% (90% CrI [68.3%, 92.4%]) and a wide 90% posterior predictive interval of 19–89%, indicating substantial variability in the PPV across populations. Most studies presented high or unclear risk of bias and applicability concerns based on QUADAS‐2 evaluation. 2D prenatal ultrasound evaluation of the fetal small intestine diameter has a moderate ability in predicting the need for postnatal surgery due to ND‐SBD conditions. The substantial between‐study heterogeneity and wide posterior predictive interval indicate considerable variation in the predictive value across populations and clinical settings, limiting the interpretation of the pooled PPV alone. Our findings highlight the need for prospective studies to better define the normal development of the fetal small intestine and identify prenatal ultrasound markers predicting non‐duodenal small bowel abnormalities.