PRENATAL ULTRASONOGRAPHIC FETAL RIB LENGTH MEASUREMENT - CORRELATION WITH GESTATIONAL-AGE

The availability of normal data on fetal rib bone length would be of v alue in a variety of circumstances under which ultrasound examinations are performed. Fetal rib length measurements were obtained in 257 sin gleton fetuses in a prospective cross-sectional study. The study popul ation consisted of pregnancies between 14 and 40 weeks with no evidenc e of growth disturbances, or structural or karyotypic abnormalities. F etal rib length, as a function of gestational age, was expressed by th e regression equation: RL = -0.5834 + 0.2030 (GA), where RL is the rib length in centimeters and GA the gestational age in weeks. The correl ation was R = 0.94 (p < 0.0001). The normal limits of fetal rib length are defined, and a high correlation between fetal rib length, gestati onal age, and other standard determinants of fetal growth is demonstra ted. Our results indicate that fetal rib length can be a useful adjunc t in determining normal fetal growth and in the management of the preg nancy with fetal skeletal dysplasia.