Objective: To evaluate the feasibility of examining the fetal ear with three-dimensional ultrasound.
Methods: In 125 pregnancies between 19 and 38 weeks of gestation, fetal ears were evaluated by three-dimensional ultrasound. The volume images with surface rendering were analyzed to depict the morphology, lying axis, orientation, and cranial location of the fetal ears.
Results: Three-dimensional images of one or both ears were successfully reconstructed in 105 fetuses. Among them, 18 fetuses had anomalous ears. The anomalous ears, including microtia, low-set ear with slope axis, abnormal ear orientation, and edematous ear, were confirmed after delivery. Three-dimensional ultrasound consistently displayed fetal ear abnormalities with greater accuracy and clarity.
Conclusion: Because anomalous ears may be a part of complex fetal malformations, it is important to recognize ear abnormalities. Due to the complexity of the fetal ear, three-dimensional ultrasound offers more important information than two-dimensional ultrasound, which simply gives auricular geometry. We suggest that three-dimensional ultrasound can be used better to examine the fetal ear and may prove to be useful for prenatal diagnosis and genetic counseling.