Thanatophoric dysplasia: ultrasound diagnosis.

Six pregnant women with singleton fetuses were referred to our Prenatal Diagnostic Centers because of an initial diagnosis of intrauterine growth restriction (n = 4) or short femoral length (n = 2). We first examined the patients with two-dimensional (2D) ultrasonography (US), and then with three-dimensional (3D) US, and arrived at a definitive diagnosis of thanatophoric dysplasia. Although in experienced hands a diagnosis of thanatophoric dysplasia can be made with 2D US before the 24th week of gestation, our experience suggests that 3D US is a valuable complement to 2D US for the evaluation of fetuses with skeletal dysplasias.