The clinical significance of sonographically detected fetal hepatic hyperechogenicities has not been fully established. The aim of this study was to assess various aspects of fetal hepatic hyperechogenicities detected in utero, including natural history, prenatal investigation and pregnancy outcome. In a retrospective survey of pregnant women presenting to the ultrasonographic unit, five fetuses with a mean gestational age of 20 weeks (range 14-24 weeks) were antenatally diagnosed as having hepatic hyperechogenicities. All cases underwent extensive investigation to establish the etiology and to determine the spectrum of ultrasonographic presentation. In three fetuses, only parenchymal lesions were found, while two had combined lesions: parenchymal and peritoneal. The earliest prenatal ultrasonographic diagnosis was made at 14 weeks' gestation in a fetus with combined hyperechogenic lesions, which, at 12 weeks' gestation, demonstrated unexplained fetal ascites. Associated abnormalities were found in only one fetus in which a solitary parenchymal lesion was associated with direct communication of the intrahepatic portion of the umbilical vein with the right atrium, and high output cardiac failure. In this case, termination of pregnancy confirmed ischemic hepatic necrosis. In the other four cases, no direct etiology could be determined, and all four pregnancies continued to term with normal neonatal follow up until 12 months of age. The present data suggest that in cases of fetal hepatic hyperechogenicities, where apparent intrauterine infection or neoplasia can be ruled out, a vascular disruption phenomenon is a putative etiology. If there are no associated morphological abnormalities or abnormal karyotypes, the prognosis may be favorable.