Fetal esophagus: normal sonographic appearance.

Our objective was to describe the sonographic appearance of the normal fetal esophagus and to determine the rate of its visualization. The fetal esophagus has a tubular echogenic appearance. Two patterns of the tubular structure were observed: two parallel echogenic lines or several parallel echogenic lines (the so-called "multilayered pattern"). A cannula was placed in the stomach of three stillborns and removed under ultrasonographic monitoring, confirming its location. In 155 consecutive pregnancies examined, the thoracic part of the fetal esophagus was easy to visualize (about 90% of cases); the cervical and abdominal segments were more difficult to visualize (19 and 30%, respectively). The multilayered pattern was observed in 49% of cases before and in 87% of cases after 26 weeks' gestation. A direct sonographic demonstration of the fetal esophagus is possible and could help to exclude esophageal malformations.