Sonography of the fetal gastrointestinal tract: anatomic variants, diagnostic pitfalls, and abnormalities

Prenatal sonography has the potential to show a wide range of abnormalities in a fetus's gastrointestinal tract. Suspected fetal gastrointestinal abnormalities should be interpreted with caution, however, as the sonographic appearance of a healthy fetus's gastrointestinal tract is variable and there is considerable overlap in the appearances of normal and abnormal fetal bowel. Similarly, pathologic processes originating from organ systems other than the gastrointestinal tract can at times exhibit sonographic patterns remarkably similar to those of dilated bowel. This review examines the sonographic findings of gastrointestinal disorders seen in utero, emphasizing potential diagnostic pitfalls arising from confusion with normal anatomy, anatomic variants, and pathologic processes elsewhere in the fetus.