Liver volume in trisomy 21 and euploid fetuses at 11 to 13 weeks.

OBJECTIVES To compare liver volume between trisomy 21 and euploid fetuses at 11 to 13 weeks' gestation. METHODS Fetal liver volume was measured by 3D ultrasound in fetuses at low risk of aneuploidies (n = 200) and another group at high risk, including 148 euploid and 37 with trisomy 21. The association of liver volume with fetal nuchal translucency (NT) thickness, tricuspid regurgitation and reversed a-wave in the ductus venosus was investigated. RESULTS In the low-risk group, fetal liver volume increased exponentially with fetal crown-rump length (CRL) from a median of 0.5 cm(3) at CRL of 45 mm to about 2.5 cm(3) at CRL of 84 mm. In 27 (73.0%) of the trisomy 21 fetuses liver volume was above the 95th percentile of the low-risk group, whereas in the euploid fetuses liver volume was not significantly altered (P = 0.521). There were no significant contributions to liver volume from fetal NT (P = 0.508), tricuspid regurgitation (P = 0.958) or reversed a-wave in the ductus venosus (P = 0.872). CONCLUSION In trisomy 21 fetuses at 11 to 13 weeks liver volume is increased.