Prenatal diagnosis of skeletal dysplasia by real-time ultrasound.

A control group of 165 normal pregnant women between 16 and 22 weeks' gestation was studied by real-time ultrasound scan to establish the normal length of the femur, tibia-fibula complex, humerus, and radius-ulna complex. A group of 32 pregnant women at risk for various types of fetal skeletal dysplasia were studied during the same gestational period. In three cases a structural defect was diagnosed, resulting in elective abortion. Conditions for optimal prenatal diagnosis of skeletal dysplasias are discussed.