<正>孕妇,27岁。孕1产0,孕22周6 d,产前筛查:β-HCG 0.142μg/L,MOM 7.67,21-三体1/240,提示21-三体高风险,有腹痛病史。孕中期行系统超声检查所见:BPD 5.8 cm,HC 19.9 cm,FL3.2 cm,HL 3.1 cm,AC 15.8 cm。侧脑室前角:左侧0.31 cm,右侧0.31 cm;体部:左侧0.86 cm,