Viora E, Errante G, Sciarrone A, Bastonero S, Masturzo B, Martiny G, Campogrande M
Ultrasound and Prenatal Diagnosis Unit, Sant'Anna Hospital, Turin, Italy.
Prenat Diagn. 2005 Jun;25(6):511-5. doi: 10.1002/pd.848.
To assess the feasibility of measuring nasal bone length in the second trimester of pregnancy and to confirm if fetal nasal bone absence or hypoplasia is a marker for Down syndrome.
Fetal nasal bone assessment was performed in 439 consecutive singleton pregnancies at high risk of Down syndrome between 15 and 21 weeks. All ultrasound examinations were performed transabdominally by five skilled sonographers. If the nasal bone was present, its length was measured. The biparietal diameter: nasal bone length ratio (BPD/NBL) was also calculated.
Nasal bone assessment was successfully achieved in all fetuses. The nasal bone was absent in 2(0.47%) of the 417 unaffected fetuses and in 10(55.5%) of the 18 fetuses with trisomy 21. Of the 8 Down syndrome cases with a nasal bone present, 4 had nasal bone hypoplasia and 4 had a normal nasal bone. BPD/NBL was 9 or greater in 7 of the 8 fetuses affected by trisomy 21 with nasal bone present and in 86 (20.6%) of the 417 normal fetuses; it was 10 or greater in 5 of the 8 (62.5%) fetuses affected by trisomy 21 and in 41 of the 417 (9.8%) euploid fetuses.
Nasal bone absence is a marker for Down syndrome in the second trimester of pregnancy. Inclusion of nasal bone length into the second-trimester screening protocol could potentially obviate the false-negative cases from other screening tests. The measurement of nasal bone length in the second trimester seems to provide additional benefits beyond the assessment of the presence or absence of the nasal bone.
评估在妊娠中期测量鼻骨长度的可行性，并确认胎儿鼻骨缺失或发育不全是否为唐氏综合征的一个标志物。
对439例连续的单胎妊娠进行胎儿鼻骨评估，这些妊娠在孕15至21周时为唐氏综合征高危妊娠。所有超声检查均由五名技术熟练的超声检查医师经腹部进行。如果鼻骨存在，则测量其长度。还计算双顶径：鼻骨长度比值（BPD/NBL）。
所有胎儿均成功完成鼻骨评估。在417例未受影响的胎儿中，有2例（0.47%）鼻骨缺失；在18例21三体胎儿中，有10例（55.5%）鼻骨缺失。在8例鼻骨存在的唐氏综合征病例中，4例鼻骨发育不全，4例鼻骨正常。在8例鼻骨存在的21三体胎儿中，7例的BPD/NBL为9或更高，在417例正常胎儿中，86例（20.6%）的BPD/NBL为9或更高；在8例21三体胎儿中，5例（62.5%）的BPD/NBL为10或更高，在417例整倍体胎儿中，41例（9.8%）的BPD/NBL为10或更高。
鼻骨缺失是妊娠中期唐氏综合征的一个标志物。将鼻骨长度纳入妊娠中期筛查方案可能会避免其他筛查试验出现假阴性病例。妊娠中期测量鼻骨长度似乎除了评估鼻骨是否存在之外还能提供额外的益处。
