To explore the pattern of the changes and etiology of fetal liver strong echo by analyzing the ultrasonographic features, in order to provide help for clinical consultation.

A retrospective study was conducted on 63 singleton pregnant women who were found to have strong echo in fetal liver on ultrasound examination at Beijing Obstetrics and Gynecology Hospital Affiliated to Capital Medical University and Beijing Luhe Hospital Affiliated to Capital Medical University from January 1, 2016 to December 31, 2019. The basic information of pregnant women, fetal measurement results, the size, shape, location, and number of fetal liver strong echoes, whether there were other fetal structural abnormalities, placenta, amniotic fluid, umbilical cord, and fetal umbilical artery blood flow were recorded. The results of chromosome examination and maternal virus series (TORCH) examination, the changes of fetal strong echo during pregnancy, and the pregnancy outcome of the included cases were followed. Neonatal birth information, post-birth growth, and strong echo reexamination of the liver were recorded in all live births. The etiology and pattern of changes of strong echo in fetal liver were explored by summarizing prenatal and postnatal data. The rank sum test was used to compare the difference in the length of prenatal lesions between the two groups with or without strong echo after birth.

Among the 63 fetuses, 17 (27%, 17/63) were associated with other fetal abnormalities, and 46 (73%, 46/63) had isolated fetal liver strong echo. Chromosome abnormality was found in two cases (3%, 2/63), and both had trisomy 21. Three pregnant women had viral infections (5%, 3/63). Meconium peritonitis occurred in one case (2%, 1/63). Among the 17 cases associated with other fetal abnormalities, two terminated pregnancy, one had neonatal death, and two received surgical treatment after birth. The postnatal information of 52 cases was followed, of which 27 still had strong echo at birth, the mean lesion length was 0.70 cm, and the median was 0.60 (0.60, 0.80) cm. The strong echo had disappeared at birth in the remaining 25 cases, the mean lesion length was 0.47 cm, and the median was 0.50 (0.40, 0.60) cm; the difference was statistically significant between the two groups (Z=3.54, P＜0.001). All live births had good outcomes.

Fetal liver strong echo are not uncommon, and some fetal liver strong echoes (smaller in length) may disappear spontaneously. The proportion of cases with isolated foci is higher than that reported in the previous literature, and the prognosis is good. Cytomegalovirus infection is the main infection. When there are other abnormalities in the fetus, it is recommended to conduct fetal chromosome examination through non-invasive DNA or amniocentesis, and to conduct chromosome microarray analysis if necessary.