Nasal Bone Measurement during the 1st Trimester: Is It Useful?

Abstract

The aim of this study was to present our preliminary data about nasal bone measurements at 11–14 weeks of pregnancy. This study was conducted in our prenatal unit between 2000 and 2003. A total of 642 pregnant women (single pregnancies) were enrolled into the study. During the first trimester of pregnancy, crown-rump length, nuchal translucency thickness, and fetal nasal bone length measurements and ductus venosus Doppler images were evaluated. The distribution of absent or small nasal bones in both normal fetuses and in those having some pathological conditions was compared by statistical analysis. p < 0.05 was considered significant. Nasal bone evaluation was successful in 600 of 642 (93.4%) ultrasound examinations. The linear regression line showed a significant positive slope with increasing crown-rump length (r = 0.54, p < 0.001). Absent or small nasal bones were more common in abnormal than in normal fetuses (p = 0.007). It is clear that the fetal nasal bone is becoming a powerful tool in prenatal screening for aneuploidy. Larger studies to be performed in a low-risk population are needed to assess whether the measurement of the nasal bone length provides additional benefits beyond the assessment of the presence or absence of the nasal bone.

Fetal Nasal Bone Length as a Novel Marker for Prediction of Adverse Perinatal Outcomes in the First-Trimester of Pregnancy

“…However, after a sufficient period of training, they may be easily incorporated to the first-trimester screening test parameters. Moreover, fetal NBL measurements in our study were comparable to previous studies from Turkey (7,15,16) and from other ethnicities (6,17). …”

“…If the NB was more echogenic and thicker than the overlying skin, it was assumed to be present. If the NB was either the same or less echogenic or it was not visualized clearly then it was assumed to be absent (6,7,8,9). The fetal NBL was measured by placing the calipers in an out-to-out position (Figure 1).…”

“…Previously, the role of nasal bone (NB) length (NBL) in screening for genetic defects was assessed (6,7). Furthermore, the possible relationship between fetal NBL and adverse perinatal outcomes is of interest.…”

Ultrasound and fetal diagnosis

“…This retrospective study suggests that adding this fourth marker (nasal bone) improves detection of trisomy 21 and reduces the initial screen-positive rate. These results agree with other studies that have shown absent [3, 4,5 ] or hypoplastic nasal bone [6] to be a useful marker for Down syndrome.…”

Avaliação ultra-sonográfica do osso nasal fetal: evolução das medidas ao longo da gestação

“…A mensuração do osso nasal nessa fase da gestação tem demonstrado reprodutibilidade inadequada 8 . Estudos prospectivos e randomizados, em populações de baixo risco, se tornam necessários para avaliar se a mensuração do comprimento do osso nasal no primeiro trimestre oferece benefício adicional além da avaliação qualitativa de sua presença ou ausência 23 . Esforços devem ser feitos para melhor padronização, treinamento e controle de qualidade para validar a medida do comprimento do osso nasal no rastreamento da síndrome de Down na população geral 8 , além de permitir comparação dos diversos trabalhos.…”