Acta Medica Medianae
Vol. 50, No 1, March, 2011
UDK 61
ISSN 0365-4478(Printed version)
ISSN 1821-2794(Online)
 

Correspondence to:

Dragan Lončar

Vojislava Kalanovića St. 1 A/3

34000 Kraguejvac

E-mail: drloncar@sezampro.rs

Original article
UDC:618.33-073.43:576.316

doi:10.5633/amm.2011.0102  

Predictive value of fetal nuchal translucency in screening of chromosomal aberrations

Dragan Lončar¹, Miroslav Stojadinović² and Slavica Lončar³

                       Clinical Center Kragujevac, Gynecology and Obstetrics Clinic¹

                       Clinical Center Kragujevac, Urology Clinic²

                       Health Center, Kragujevac³

In search for specific early ultrasound signs that could indicate an increased risk of hereditary or acquired disorders of the fetus, scientific researches confirm the value of exceptional ultrasound findings of nuchal translucencey (NT).

The aim of the study was to determine the predictive value of the diameter of fetal NT in the detection of chromosomopathy.

The investigation included 317 pregnant women with monofetal pregnancies, gestational age 11-14 weeks. The control group consisted of pregnant women in whom, after amniocentesis, a regular result of fetal karyotype was obtained. The limits of physiological and pathological findings of the NT value were not determined; instead, we used the diameters of NT that were obtained in pregnant women with pathological score of amniocentesis as potentially pathological values.

Mean value of NT in the control group was 1.92±0.39mm, and in the group with pathological findings of fetal karyotype it was 2.49±0.37mm, which is a statistically significant difference (p<0.05). Mean value of the rump-crown length in the control group was 64.83±8.23mm, and the group with pathological karyotype 60.12±8.48mm; gestational age in the control group was 7.10±87.40 days, and in the pathological one 85.69±3.98 days, which speaks of homogeneity of the investigated sample (p>0.05).The probability that a patient with negative NT findings be healthy is 0.97. NT sensitivity as a marker for chromosomopathy was 0.97. The rate of false positive findings was 0.027. Specificity of NT as a marker for chromosomopathy was 0.97. The probability that a patient with positive findings NT really be ill was 0.66.

Valid findings of NT can be considered safe ultrasonographic markers in the assessment of absence of chromosomopathy. Pathological finding, given the low positive predictive value of NT, must be amended by other prenatal tests before a pregnant woman is advised on prenatal invasive diagnostics. Acta Medica Medianae 2011;50(1):11-16.

Key words: nuchal translucency, ultrasonography, chromosomopathy, predictive statistics