Paradoxical motion: a useful tool in the prenatal diagnosis of congenital diaphragmatic hernias and eventrations.

Objective. The purpose of this series was to determine whether paradoxical motion of the diaphragm reliably identifies congenital diaphragmatic hernias (CDHs). Methods. Sonographic evaluation of diaphragmatic motion was attempted in all fetuses undergoing a targeted examination for findings suggestive of a possible CDH. During any respiratory motion or hiccupping, the posterior chest and abdomen were visualized in a coronal plane at the level of the descending aorta to evaluate ascent and descent of the hemidiaphragms. Normal motion was defined as descent of both during inspiration. Paradoxical motion was defined as descent of one hemidiaphragm and ascent of the opposite one during inspiration. If no breathing motion was observed during the examination, the results were termed “poor visualization.” If there was poor visualization, the diaphragm was reevaluated at any return visits. In the second part of this study, diaphragmatic motion in 120 fetuses of at least 15 weeks’ gestational age without abnormalities was evaluated. The diagnosis of a CDH needed to be confirmed by pathologic examination or surgery. Results. No fetus without abnormalities showed paradoxical breathing. There were 15 fetuses who had a confirmed CDH and showed breathing during an examination. Fourteen of 15 had paradoxical motion; the fetus who did not had a very small defect containing a single loop of bowel. Thirteen fetuses had CDHs, and 2 had eventrations. Conclusions. Paradoxical motion is specific for CDHs and eventrations and can be seen as early as 17 weeks’ gestation. Key words: diaphragm; eventration; fetus; hernia; paradoxical breathing.