Severe micrognathia with 21 trisomy assessed prenatally by performing three-dimensional computed tomography.

Severe micrognathia can lead to death shortly after birth without a proper resuscitation. However, it is difficult to develop an effective resuscitation strategy without a prenatal diagnosis of the severity of micrognathia. In the present case, we used fetal three-dimensional computed tomography (3D-CT) to assess the severity of micrognathia. Its images clearly demonstrated bony framework of mandible and suggested that mandibular hypoplasia was too severe to allow for oral intubation. We therefore decided that the ex utero intrapartum treatment (EXIT) procedure would be more appropriate to establish the airway at birth. The prenatal 3D-CT is useful to evaluate the mandibular anatomy in utero if the severity of the micrognathia is not confirmed by the ultrasound or magnetic resonance imaging (MRI).