Prenatal diagnosis with chromosome microarray and pregnancy outcomes of fetuses with biliary tract system abnormalities.

Objectives: To investigate the prenatal diagnostic value of chromosome microarray analysis (CMA) in fetuses presenting with ultrasound-based biliary tract system (BTS) anomalies.

Methods: Amniocentesis was performed and CMA was applied in 271 pregnant women carrying fetuses with BTS abnormalities between April 2015 and December 2020. Pregnancy outcomes and fetal prognosis were followed from 1 to 6 years.

Results: Sixteen cases (5.9%, 16/271) of chromosomal anomalies were detected. The detection rate of chromosomal abnormalities was significantly higher for fetuses with nonisolated BTS anomalies than for those with isolated BTS anomalies (9.0% vs. 0%, p = 0.0017). Follow-up results were obtained from 267 fetuses, including 25 cases of termination of pregnancy (9.4%), 237 live births (88.8%), and 5 (1.9%) neonatal demises. The incidence of congenital biliary atresia in the small gallbladder and nonvisualized gallbladder groups was 3.0% (1/33) and 9.5% (7/74), respectively; however, none was detected on postnatal ultrasound reexamination in the gallbladder enlargement or the other BTS groups.

Conclusions: An isolated BTS abnormality is not an indication for invasive prenatal chromosomal analysis. When combined with other ultrasonographic abnormalities, prenatal CMA should be provided. When a small or nonvisualized gallbladder is found prenatally, ultrasonography is limited in the differential diagnosis of congenital biliary atresia.