Sonographic estimation of fetal liver weight: an additional biometric parameter for assessment of fetal growth.

A single fetal ultrasonogram was obtained between the 20th and 40th weeks of gestation in 327 pregnancies. Fetal body weight was calculated with standard methods and fetuses were classified as appropriate for gestational age (303 fetuses), large for gestational age (four fetuses), or small for gestational age (20 fetuses). Fetal liver weight was estimated on the basis of longitudinal, anteroposterior, and cephalocaudal liver dimensions multiplied by a constant (k) of 0.42 determined experimentally in a previous study of adult livers. Estimated liver weights in appropriate for gestational age fetuses were not statistically different from published standards based on autopsy findings (P < 0.005). Similar findings were obtained in two other normal pregnancies examined serially until delivery. Estimation of fetal liver weight appears to be an accurate and reproducible method and may enhance sonographic assessment of fetal growth abnormalities and conditions with fetal liver involvement.