Nasal bone (NB) length measurement in the first trimester of pregnancy in Polish population and its validity as fetal aneuploidy indicator

Abstract

Objectives: Dynamic development of prenatal diagnostics is mostly directed towards search for non-invasive screening. The main role of the screening methods is to select high-risk fetal aneuploidy group of pregnant women. The base for the prenatal screening in modern obstetrics is ultrasound scanning. Design: The aim of the study was to estimate typical value range for the fetal nasal bone length measurement (NB) between 11th and 20th week of pregnancy, in Polish population. The second aim was to assess the value of the parameter as an aneuploidy marker. Materials and methods: The study was conducted between 1999-2006, in the 1st Division of Obstetrics and Gynaecology, Medical University in ¸ode. The investigated population comprised 2960 pregnant women. 53 cases of the fetal chromosomal aneuploidies were diagnosed. Results: Typical values for the nasal bone measurement were estimated. The investigations showed that until 13th gestation week, visualization of the presence or absence of the nasal bone on the ultrasound scan is a better marker for fetal aneuploidy diagnosis than the measurement. However, since the 14th week, it is the measurement that becomes the most adequate method of the fetal nasal bone assessment. Conclusions: 1. We estimated the normal value range for the fetal nasal bone length measurement (NB) between 11 and 20 weeks of pregnancy. 2. The nasal bone length is an useful marker for the fetal aneuploidy. 3. The predictive value of the method suggests the visualization of the nasal bone presence in the 1st trimester of the pregnancy as a screening method. The measurement of the NB proves to be a useful method in the prenatal diagnostic in the 2nd trimester of the pregnancy.