Enlarged fetal gallbladder: prognostic importance for aneuploidy or biliary abnormality at antenatal US.
PURPOSE: To test the strength of the association of cholecystomegaly with aneuploidy and biliary abnormality and to assess the prognostic importance of the detection of an enlarged fetal gallbladder at antenatal ultrasonography (US). MATERIALS AND METHODS: Gallbladder size was prospectively evaluated during 842 consecutive second-and third-trimester US examinations in 775 fetuses. The area of the gallbladder was calculated on the image that depicted the maximal gallbladder size, and the actual gallbladder areas was compared with the gallbladder area expected on the basis of the gestational age. Fetuses with an enlarged gallbladder were followed up. RESULTS: Forty-three fetuses had an enlarged gallbladder (area more than 2 SDs above the mean for gestational age). Outcome was normal in 38 of the 39 fetuses who could be followed up. With the exception of a single baby with an isolated ventricular septal defect, which closed spontaneously, none of the babies with an enlarged fetal gallbladder had structural anatomic defects or evidence of aneuploidy or a biliary tract abnormality. CONCLUSION: Identification of an enlarged gallbladder at antenatal US does not appear to be associated with a substantially increased risk of chromosomal aneuploidy or biliary tract malformation.