Can transvaginal fetal biometry be considered a useful tool for early detection of skeletal dysplasias in high-risk patients?

Objective To evaluate the possibility of an early diagnosis of skeletal dys plasias in high-risk patients. Methods A total of 149 consecutive, uncomplicated singleton Pregnancies at 9-13 weeks' amenorrhea, with certain menstrual history and regular cycles, were investigated with transvaginal ultrasound to establish the relationshi p between femur length and menstrual age, biparietal diameter and crown-rum p length, using a poly-nomial regression model. A further eight patients wi th previous skeletal dysplasias in a total of 13 pregnancies were evaluated with serial examinations every 2 weeks from 10-11 weeks. Results A significant correlation between femur length and croton-rump leng th and biparietal diameter was found whereas none was observed between femu r length and menstrual age. Of the five cases with skeletal dysplasias, onl y two (one with recurrent osteogenesis imperfecta and one with recurrent ac hondrogenesis) were diagnosed in the first trimester. Conclusions An early evaluation of fetal morphology in conjunction with the use of biometric charts of femur length against crown-rump length and femu r length against biparietal diameter may be crucial for early diagnosis of severe skeletal dysplasias. By contrast, in less severe cases, biometric ev aluation appears to be of no value for diagnosis.