Twins discordant for fetal skeletal abnormalities: a natural confrontation between the two siblings.

ABSTRACT

BACKGROUND: Skeletal abnormalities encompass a heterogeneous group of disorders characterized by anomalies of cartilage as well as bone growth and development. Some are lethal and express early during fetal life, making them amenable to prenatal diagnosis. The increasing use of routine ultrasonography (US) during pregnancy permits a reliable primary evaluation of the fetal skeleton. However, when a skeletal dysplasia is suspected, it is more difficult to establish a specific diagnosis. Moreover, detailed ultrasonographic evaluation of the whole fetal skeleton may be limited in some circumstances, especially during the third trimester due to the fetal position and in the case of multiple pregnancies. METHODS: Retrospective study of twin pregnancies complicated with skeletal abnormalities. RESULTS: 6 twin pregnancies were reviewed. The prenatal diagnosis was correctly made in 66.66% (4/6) with the primary use of combined 2D and 3D-US. 3D-HCT permits to improve the simultaneous assessment of both fetuses, and is of greater value than US in 16.66% (1/6). CONCLUSION: The combined use of 2D or 3D-US with 3D-HCT permits the best imaging evaluation.