Yields of aneuploidy and correlation with ultrasonographic findings
Among all isolated ultrasonographic anomalies, the fetal hydrops had the highest yield of aneuploidy (34.85%), followed by cystic hygroma (24.76%), and abdominal wall defect (13.71%) (Table 2). Among all isolated soft markers, the increased nuchal translucency had the highest yield of aneuploidy (12.43%), followed by absent or hypoplastic nasal bone (6.63%) and thickened nuchal fold (5.47%)(Table 3).
We observed that the yields of aneuploidy increased with the number of anomalies or soft markers. When fetuses presented with multiple ultrasonographic anomalies or soft markers, the yields of aneuploidy increased from 5.05% (597/11,818) to 28.83% (79/274) and 6.98% (1,107/15,856) to 16.81% (20/119), respectively. Specifically, the yield of aneuploidy in fetuses with both fetal hydrops and cystic hygroma was up to 64.94% (50/77) (Table S2). The yield of aneuploidies in fetuses with increased nuchal translucency and absent or hypoplastic nasal bone was as high as 61.63% (53/86) (Table S3).
Overall, three aneuploidies, including trisomy 18, 45,X syndrome, and trisomy 13,
were significantly associated with ultrasonographic anomalies, while trisomy 21 was significantly associated with soft markers (Figure S2A ). Specifically, trisomy 21 significantly associated with soft markers such as absent or hypoplastic nasal bone, increased nuchal translucency, and thickened nuchal fold, as well as with
ultrasonographic anomalies, including cystic hygroma and fetal hydrops (Figure S2B). Trisomy 18 was significantly associated with soft markers and ultrasonographic anomalies, presenting in three types of soft markers (single umbilical artery, increased
nuchal translucency, and choroid plexus cysts) and ultrasonographic anomalies (fetal
hydrops, cystic hygroma, and abdominal wall defect). Both 47,XXY and 47,XYY syndromes tended to occur with normal ultrasonographic findings and showed no significant association with soft markers and ultrasonographic anomalies. In addition, 45,X syndrome was significantly associated with increased nuchal translucency, fetal hydrops, and cystic hygroma, while trisomy 13 was significantly associated with abdominal wall defect and increased nuchal translucency (Figure S2B).