The authors concluded that antenatal diagnosis of skeletal dysplasias is problematic: In their series, only 20 of 31 cases were correctly diagnosed. ^[22]However, the antenatal prediction of lethality was highly accurate. The most common predictors of lethal skeletal dysplasias included early and severe shortening of the long bones, femur length–abdominal circumference ratio of less than 0.16, hypoplastic thorax, and certain distinguishing characteristics. ^[22]