Three-Dimensional Prenatal Ultrasonography of Thanatophoric Dysplasia: Initial Experience at Siriraj Hospital

Objective: To initially report the prenatal diagnosis of thanatophoric dysplasia (TD) by using both 2 dimensional (2D-US) and 3 dimensional (3D-US) ultrasonography. Methods: During January 2004 to December 2006, 10 pregnant women who were referred to our Maternal Fetal Medicine Unit due to abnormal skeletal sonographic findings have been extensively investigated by 2D-US and 3D-US. Results: 3 cases of TD (30%) have been identified with an average gestational age of 26 weeks. Sonographic findings demonstrated short limbs, severe micromelia, telephone receiver like femoral bone, bell shaped small thorax, platyspondyly of vertebrae and normal shaped skull in all cases. Prenatal diagnosis was made earlier by 2D-US analysis and then was confirmed by 3D-US. Conclusion: 3D-US provides additional findings and increases interpreter confidence. It provides additional information in the evaluation of fetal skeletal dysplasia, including thanatophoric dysphasia, compared with 2D-US